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Background: We assessed associations between binding antibody (bAb) concentration <5 days from symptom onset and testing positive for COVID-19 among patients in a test-negative study., Methods: From October 2021 to June 2022, study sites in 7 states enrolled patients aged ≥6 months presenting with acute respiratory illness. Respiratory specimens were tested for SARS-CoV-2. In blood specimens, we measured concentrations of anti-SARS-CoV-2 antibodies against the spike protein receptor binding domain (RBD) and nucleocapsid antigens from the ancestral strain in standardized bAb units (BAU). Percentage change in odds of COVID-19 by increasing anti-RBD bAb was estimated via logistic regression as (1 - adjusted odds ratio of COVID-19) × 100, adjusting for COVID-19 mRNA vaccine doses, age, site, and high-risk exposure., Results: Out of 2018 symptomatic patients, 662 (33%) tested positive for acute SARS-CoV-2 infection. Geometric mean RBD bAb levels were lower among COVID-19 cases than SARS-CoV-2 test-negative controls during the Delta-predominant period (112 vs 498 BAU/mL) and Omicron-predominant period (823 vs 1189 BAU/mL). Acute-phase ancestral spike RBD bAb levels associated with 50% lower odds of COVID-19 were 1968 BAU/mL against Delta and 3375 BAU/mL against Omicron; thresholds may differ in other laboratories., Conclusions: During acute illness, antibody concentrations against ancestral spike RBD were associated with protection against COVID-19., Competing Interests: Potential conflicts of interest. R. K. Z. reports grants from the CDC during the conduct of the study and grants from Sanofi Pasteur outside the submitted work. C. G. G. reports other from the CDC, grants from the National Institutes of Health, other from the Food and Drug Administration, grants and other from the Agency for Healthcare Research and Quality, other from Merck, and other from Syneos Health, outside the submitted work. H. K. T. reports grants from the CDC during the conduct of the study. E. A. B. reports grants from the CDC during the conduct of the study. E. T. M. reports grants from the CDC during the conduct of the study and grants from Merck outside the submitted work. M. G. reports grants from the CDC during the conduct of the study and grants from the CDC, CDC-Vanderbilt, and CDC–Abt Associates, outside the submitted work. M. G. is also cochair of the Infectious Diseases and Immunization Committee, Texas Pediatric Society, Texas Chapter of the American Academy of Pediatrics. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest., (Published by Oxford University Press on behalf of Infectious Diseases Society of America 2024.)

We describe humoral immune responses in 105 ambulatory patients with laboratory-confirmed SARS-CoV-2 Omicron variant infection. In dried blood spot (DBS) collected within 5 days of illness onset and during convalescence, we measured binding antibody (bAb) against ancestral spike protein receptor binding domain (RBD) and nucleocapsid (N) protein using a commercial multiplex bead assay. Geometric mean bAb concentrations against RBD increased by a factor of 2.5 from 1258 to 3189 units/mL and by a factor of 47 against N protein from 5.5 to 259 units/mL between acute illness and convalescence; lower concentrations were associated with greater geometric mean ratios. Paired DBS specimens may be used to evaluate humoral response to SARS-CoV-2 infection., (Published 2024. This article is a U.S. Government work and is in the public domain in the USA. Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd.)

Importance: On June 21, 2023, the Centers for Disease Control and Prevention recommended the first respiratory syncytial virus (RSV) vaccines for adults aged 60 years and older using shared clinical decision-making. Understanding the severity of RSV disease in adults can help guide this clinical decision-making., Objective: To describe disease severity among adults hospitalized with RSV and compare it with the severity of COVID-19 and influenza disease by vaccination status., Design, Setting, and Participants: In this cohort study, adults aged 18 years and older admitted to the hospital with acute respiratory illness and laboratory-confirmed RSV, SARS-CoV-2, or influenza infection were prospectively enrolled from 25 hospitals in 20 US states from February 1, 2022, to May 31, 2023. Clinical data during each patient's hospitalization were collected using standardized forms. Data were analyzed from August to October 2023., Exposures: RSV, SARS-CoV-2, or influenza infection., Main Outcomes and Measures: Using multivariable logistic regression, severity of RSV disease was compared with COVID-19 and influenza severity, by COVID-19 and influenza vaccination status, for a range of clinical outcomes, including the composite of invasive mechanical ventilation (IMV) and in-hospital death., Results: Of 7998 adults (median [IQR] age, 67 [54-78] years; 4047 [50.6%] female) included, 484 (6.1%) were hospitalized with RSV, 6422 (80.3%) were hospitalized with COVID-19, and 1092 (13.7%) were hospitalized with influenza. Among patients with RSV, 58 (12.0%) experienced IMV or death, compared with 201 of 1422 unvaccinated patients with COVID-19 (14.1%) and 458 of 5000 vaccinated patients with COVID-19 (9.2%), as well as 72 of 699 unvaccinated patients with influenza (10.3%) and 20 of 393 vaccinated patients with influenza (5.1%). In adjusted analyses, the odds of IMV or in-hospital death were not significantly different among patients hospitalized with RSV and unvaccinated patients hospitalized with COVID-19 (adjusted odds ratio [aOR], 0.82; 95% CI, 0.59-1.13; P = .22) or influenza (aOR, 1.20; 95% CI, 0.82-1.76; P = .35); however, the odds of IMV or death were significantly higher among patients hospitalized with RSV compared with vaccinated patients hospitalized with COVID-19 (aOR, 1.38; 95% CI, 1.02-1.86; P = .03) or influenza disease (aOR, 2.81; 95% CI, 1.62-4.86; P < .001)., Conclusions and Relevance: Among adults hospitalized in this US cohort during the 16 months before the first RSV vaccine recommendations, RSV disease was less common but similar in severity compared with COVID-19 or influenza disease among unvaccinated patients and more severe than COVID-19 or influenza disease among vaccinated patients for the most serious outcomes of IMV or death.

Background: Symptoms of COVID-19 including fatigue and dyspnea, may persist for weeks to months after SARS-CoV-2 infection. This study compared self-reported disability among SARS-CoV-2-positive and negative persons with mild to moderate COVID-19-like illness who presented for outpatient care before widespread COVID-19 vaccination., Methods: Unvaccinated adults with COVID-19-like illness enrolled within 10 days of illness onset at three US Flu Vaccine Effectiveness Network sites were tested for SARS-CoV-2 by molecular assay. Enrollees completed an enrollment questionnaire and two follow-up surveys (7-24 days and 2-7 months after illness onset) online or by phone to assess illness characteristics and health status. The second follow-up survey included questions measuring global health, physical function, fatigue, and dyspnea. Scores in the four domains were compared by participants' SARS-CoV-2 test results in univariate analysis and multivariable Gamma regression., Results: During September 22, 2020 - February 13, 2021, 2712 eligible adults were enrolled, 1541 completed the first follow-up survey, and 650 completed the second follow-up survey. SARS-CoV-2-positive participants were more likely to report fever at acute illness but were otherwise comparable to SARS-CoV-2-negative participants. At first follow-up, SARS-CoV-2-positive participants were less likely to have reported fully or mostly recovered from their illness compared to SARS-CoV-2-negative participants. At second follow-up, no differences by SARS-CoV-2 test results were detected in the four domains in the multivariable model., Conclusion: Self-reported disability was similar among outpatient SARS-CoV-2-positive and -negative adults 2-7 months after illness onset., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Background: Prolonged SARS-CoV-2 infections in people who are immunocompromised might predict or source the emergence of highly mutated variants. The types of immunosuppression placing patients at highest risk for prolonged infection have not been systematically investigated. We aimed to assess risk factors for prolonged SARS-CoV-2 infection and associated intrahost evolution., Methods: In this multicentre, prospective analysis, participants were enrolled at five US medical centres. Eligible patients were aged 18 years or older, were SARS-CoV-2-positive in the previous 14 days, and had a moderately or severely immunocompromising condition or treatment. Nasal specimens were tested by real-time RT-PCR every 2-4 weeks until negative in consecutive specimens. Positive specimens underwent viral culture and whole genome sequencing. A Cox proportional hazards model was used to assess factors associated with duration of infection., Findings: From April 11, 2022, to Oct 1, 2022, 156 patients began the enrolment process, of whom 150 were enrolled and included in the analyses. Participants had B-cell malignancy or anti-B-cell therapy (n=18), solid organ transplantation or haematopoietic stem-cell transplantation (HSCT; n=59), AIDS (n=5), non-B-cell malignancy (n=23), and autoimmune or autoinflammatory conditions (n=45). 38 (25%) participants were real-time RT-PCR-positive and 12 (8%) were culture-positive 21 days or longer after initial SARS-CoV-2 detection or illness onset. Compared with the group with autoimmune or autoinflammatory conditions, patients with B-cell dysfunction (adjusted hazard ratio 0·32 [95% CI 0·15-0·64]), solid organ transplantation or HSCT (0·60 [0·38-0·94]), and AIDS (0·28 [0·08-1·00]) had longer duration of infection, defined as time to last positive real-time RT-PCR test. There was no significant difference in the non-B-cell malignancy group (0·58 [0·31-1·09]). Consensus de novo spike mutations were identified in five individuals who were real-time RT-PCR-positive longer than 56 days; 14 (61%) of 23 were in the receptor-binding domain. Mutations shared by multiple individuals were rare (<5%) in global circulation., Interpretation: In this cohort, prolonged replication-competent omicron SARS-CoV-2 infections were uncommon. Within-host evolutionary rates were similar across patients, but individuals with infections lasting longer than 56 days accumulated spike mutations, which were distinct from those seen globally. Populations at high risk should be targeted for repeated testing and treatment and monitored for the emergence of antiviral resistance., Funding: US Centers for Disease Control and Prevention., Competing Interests: Declaration of interests JDC reports receiving grants from the National Institutes of Health (NIH) and the Department of Defense, outside the submitted work. CGG reports grants from NIH, the Centers for Disease Control and Prevention (CDC), the Agency for Healthcare Research and Quality, the US Food and Drug Administration, and Campbell Alliance/Syneos Health, and consulting fees and participating on a data safety monitoring board for Merck, outside the submitted work. AEF reports a K08 award from NIH and participating on the Hennepin Health Research Institute Board of Directors, outside the submitted work. NH reports grants from Sanofi, Quidel, and Merck, outside the submitted work. ASL reports receiving grants from CDC, National Institute of Allergy and Infectious Diseases, Burroughs Wellcome Fund, and Flu Lab, and consulting fees from Roche, outside the submitted work. ETM reports receiving a grant from Merck, outside the submitted work. All other authors declare no competing interests., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

In September 2023, CDC's Advisory Committee on Immunization Practices recommended updated 2023-2024 (monovalent XBB.1.5) COVID-19 vaccination for all persons aged ≥6 months to prevent COVID-19, including severe disease. However, few estimates of updated vaccine effectiveness (VE) against medically attended illness are available. This analysis evaluated VE of an updated COVID-19 vaccine dose against COVID-19-associated emergency department (ED) or urgent care (UC) encounters and hospitalization among immunocompetent adults aged ≥18 years during September 2023-January 2024 using a test-negative, case-control design with data from two CDC VE networks. VE against COVID-19-associated ED/UC encounters was 51% (95% CI = 47%-54%) during the first 7-59 days after an updated dose and 39% (95% CI = 33%-45%) during the 60-119 days after an updated dose. VE estimates against COVID-19-associated hospitalization from two CDC VE networks were 52% (95% CI = 47%-57%) and 43% (95% CI = 27%-56%), with a median interval from updated dose of 42 and 47 days, respectively. Updated COVID-19 vaccine provided increased protection against COVID-19-associated ED/UC encounters and hospitalization among immunocompetent adults. These results support CDC recommendations for updated 2023-2024 COVID-19 vaccination. All persons aged ≥6 months should receive updated 2023-2024 COVID-19 vaccine., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Steven Y. Chang reports consulting fees from PureTech Health and Kiniksa Pharmaceuticals, and participation on the data safety monitoring board for an unrelated, local study at Ronald Reagan UCLA Medical Center, outside the submitted work. Manjusha Gaglani reports serving as the Texas Pediatric Society, Texas Chapter of the American Academy of Pediatrics co-chair of the ID and Immunization Committee, outside the submitted work. Adit A. Ginde reports support from Biomeme and Seastar, outside the submitted work. Carlos G. Grijalva reports other funding from Merck, contracts from Syneos Health and the Food and Drug Administration, and grants from National Institutes of Health (NIH) and Agency for Health Care Research and Quality, outside the submitted work. Akram Khan reports grant funding from 4DMedical, Dompe Pharmaceuticals, Ely Lilly, and Roche Pharmaceuticals, outside the submitted work. Adam S. Lauring reports research support from the National Institute of Allergy and Infectious Diseases, Michigan Department of Health and Human Services, Burroughs Wellcome Fund, Flu Lab, and consulting fees from Roche, outside the submitted work. Christopher Mallow reports medical legal consulting, outside the submitted work. Emily T. Martin reports research funding from Merck, outside the submitted work. Ithan D. Peltan reports grant support from NIH, Intermountain Research and Medical Foundation, and Janssen Pharmaceuticals, and funding to his institution from Bluejay Diagnostics and Regeneron, outside the submitted work. Karthik Natarajan reports institutional support from NIH, Office of the Director, the National Center for Advancing Translational Sciences, and the National Heart, Lung, and Blood Institute. Brian E. Dixon reports Institutional support from NIH, National Library of Medicine in the form of a T15 training grant in biomedical informatics, salary support from the U.S. Department of Veterans Affairs, royalties from Elsevier, Inc. for a book on health information technology and from Springer Nature for a book on health information technology. Nicola P. Klein reports support from GSK, Merck, Pfizer, Sanofi Pasteur, and Seqirus for work unrelated to this report. No other potential conflicts of interest were disclosed.

Importance: Bivalent mRNA COVID-19 vaccines were recommended in the US for children and adolescents aged 12 years or older on September 1, 2022, and for children aged 5 to 11 years on October 12, 2022; however, data demonstrating the effectiveness of bivalent COVID-19 vaccines are limited., Objective: To assess the effectiveness of bivalent COVID-19 vaccines against SARS-CoV-2 infection and symptomatic COVID-19 among children and adolescents., Design, Setting, and Participants: Data for the period September 4, 2022, to January 31, 2023, were combined from 3 prospective US cohort studies (6 sites total) and used to estimate COVID-19 vaccine effectiveness among children and adolescents aged 5 to 17 years. A total of 2959 participants completed periodic surveys (demographics, household characteristics, chronic medical conditions, and COVID-19 symptoms) and submitted weekly self-collected nasal swabs (irrespective of symptoms); participants submitted additional nasal swabs at the onset of any symptoms., Exposure: Vaccination status was captured from the periodic surveys and supplemented with data from state immunization information systems and electronic medical records., Main Outcome and Measures: Respiratory swabs were tested for the presence of the SARS-CoV-2 virus using reverse transcriptase-polymerase chain reaction. SARS-CoV-2 infection was defined as a positive test regardless of symptoms. Symptomatic COVID-19 was defined as a positive test and 2 or more COVID-19 symptoms within 7 days of specimen collection. Cox proportional hazards models were used to estimate hazard ratios for SARS-CoV-2 infection and symptomatic COVID-19 among participants who received a bivalent COVID-19 vaccine dose vs participants who received no vaccine or monovalent vaccine doses only. Models were adjusted for age, sex, race, ethnicity, underlying health conditions, prior SARS-CoV-2 infection status, geographic site, proportion of circulating variants by site, and local virus prevalence., Results: Of the 2959 participants (47.8% were female; median age, 10.6 years [IQR, 8.0-13.2 years]; 64.6% were non-Hispanic White) included in this analysis, 25.4% received a bivalent COVID-19 vaccine dose. During the study period, 426 participants (14.4%) had laboratory-confirmed SARS-CoV-2 infection. Among these 426 participants, 184 (43.2%) had symptomatic COVID-19, 383 (89.9%) were not vaccinated or had received only monovalent COVID-19 vaccine doses (1.38 SARS-CoV-2 infections per 1000 person-days), and 43 (10.1%) had received a bivalent COVID-19 vaccine dose (0.84 SARS-CoV-2 infections per 1000 person-days). Bivalent vaccine effectiveness against SARS-CoV-2 infection was 54.0% (95% CI, 36.6%-69.1%) and vaccine effectiveness against symptomatic COVID-19 was 49.4% (95% CI, 22.2%-70.7%). The median observation time after vaccination was 276 days (IQR, 142-350 days) for participants who received only monovalent COVID-19 vaccine doses vs 50 days (IQR, 27-74 days) for those who received a bivalent COVID-19 vaccine dose., Conclusion and Relevance: The bivalent COVID-19 vaccines protected children and adolescents against SARS-CoV-2 infection and symptomatic COVID-19. These data demonstrate the benefit of COVID-19 vaccine in children and adolescents. All eligible children and adolescents should remain up to date with recommended COVID-19 vaccinations.

We investigated the design and analysis of observational booster vaccine effectiveness (VE) studies by performing a scoping review of booster VE literature with a focus on study design and analytic choices. We then applied 20 different approaches, including those found in the literature, to a single dataset from Michigan Medicine. We identified 80 studies in our review, including over 150 million observations in total. We found that while protection against infection is variable and dependent on several factors including the study population and time period, both monovalent boosters and particularly the bivalent booster offer strong protection against severe COVID-19. In addition, VE analyses with a severe disease outcome (hospitalization, intensive care unit admission, or death) appear to be more robust to design and analytic choices than an infection endpoint. In terms of design choices, we found that test-negative designs and their variants may offer advantages in statistical efficiency compared to cohort designs.

Both SARS-CoV-2 and influenza virus can be transmitted by asymptomatic, presymptomatic, or symptomatic infected persons. We assessed effects on work attendance while ill before and during the COVID-19 pandemic in the United States by analyzing data collected prospectively from persons with acute respiratory illnesses enrolled in a multistate study during 2018-2022. Persons with previous hybrid work experience were significantly less likely to work onsite on the day before through the first 3 days of illness than those without that experience, an effect more pronounced during the COVID-19 pandemic than during prepandemic influenza seasons. Persons with influenza or COVID-19 were significantly less likely to work onsite than persons with other acute respiratory illnesses. Among persons with positive COVID-19 test results available by the second or third day of illness, few worked onsite. Hybrid and remote work policies might reduce workplace exposures and help reduce spread of respiratory viruses.

On June 21, 2023, CDC's Advisory Committee on Immunization Practices recommended respiratory syncytial virus (RSV) vaccination for adults aged ≥60 years, offered to individual adults using shared clinical decision-making. Informed use of these vaccines requires an understanding of RSV disease severity. To characterize RSV-associated severity, 5,784 adults aged ≥60 years hospitalized with acute respiratory illness and laboratory-confirmed RSV, SARS-CoV-2, or influenza infection were prospectively enrolled from 25 hospitals in 20 U.S. states during February 1, 2022-May 31, 2023. Multivariable logistic regression was used to compare RSV disease severity with COVID-19 and influenza severity on the basis of the following outcomes: 1) standard flow (<30 L/minute) oxygen therapy, 2) high-flow nasal cannula (HFNC) or noninvasive ventilation (NIV), 3) intensive care unit (ICU) admission, and 4) invasive mechanical ventilation (IMV) or death. Overall, 304 (5.3%) enrolled adults were hospitalized with RSV, 4,734 (81.8%) with COVID-19 and 746 (12.9%) with influenza. Patients hospitalized with RSV were more likely to receive standard flow oxygen, HFNC or NIV, and ICU admission than were those hospitalized with COVID-19 or influenza. Patients hospitalized with RSV were more likely to receive IMV or die compared with patients hospitalized with influenza (adjusted odds ratio = 2.08; 95% CI = 1.33-3.26). Among hospitalized older adults, RSV was less common, but was associated with more severe disease than COVID-19 or influenza. High disease severity in older adults hospitalized with RSV is important to consider in shared clinical decision-making regarding RSV vaccination., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Samuel M. Brown reports that ReddyPort pays royalties on his invention of an airway device, outside the submitted work. Jonathan D. Casey reports a travel grant from Fisher and Paykel, outside the submitted work. Steven Y. Chang reports consulting fees from PureTech Health and Kiniksa Pharmaceuticals and participation as a data safety monitoring board member for a study at University of California, Los Angeles outside the submitted work. James D. Chappell reports participating as a coinvestigator for a Merck investigator studies program, where he supported surveillance of respiratory syncytial virus infection among hospitalized children in Jordan, outside the submitted work. Manjusha Gaglani reports grants from Abt Associates and Westat, having served as cochair of the Infectious Diseases and Immunization Committee for the Texas Pediatric Society (TPS), and receiving an honorarium for serving as a TPS Project Firstline webinar speaker panelist for Respiratory Virus Review: Clinical Considerations and IPC Guidance, outside the submitted work. Adit A. Ginde reports receiving grants from the National Institutes of Health (NIH), U.S. Department of Defense, AbbVie, and Faron Pharmaceuticals outside the submitted work. Michelle N. Gong reports a grant from NIH outside the submitted work. Carlos G. Grijalva reports grants from NIH, the Agency for Healthcare Research and Quality, Food and Drug Administration, and Syneos Health, and receipt of compensation for participation in an advisory board for Merck outside the submitted work. Natasha Halasa reports receiving grants from Sanofi, Merck, and Quidel outside the submitted work. Akram Khan reports receiving grants from United Therapeutics, Johnson & Johnson, 4D Medical, Eli Lily, Dompe Pharmaceuticals, and GSK outside the submitted work. Adam S. Lauring reports receiving grants from FluLab, NIH/National Institute of Allergy and Infectious Diseases, and Burroughs Wellcome Fund and fees from Sanofi and Roche for consulting on oseltamivir and baloxavir respectively, outside the submitted work. Emily T. Martin reports a grant from Merck outside the submitted work. Christopher Mallow reports medical legal consulting outside the submitted work. Ithan D. Peltan reports grants from NIH and Janssen Pharmaceuticals and institutional support from Asahi Kasei Pharma and Regeneron outside the submitted work. Mayur Ramesh reports participating in a nonbranded speaker program supported by AstraZeneca and serving on an advisory board for Moderna outside the submitted work. No other potential conflicts of interest were disclosed.

Importance: SARS-CoV-2 surveillance studies in US child care centers (CCCs) in the post-COVID-19 vaccine era are needed to provide information on incidence and transmission in this setting., Objective: To characterize SARS-CoV-2 incidence and transmission in children attending CCCs (students) and their child care providers (CCPs) and household contacts., Design, Setting, and Participants: This prospective surveillance cohort study was conducted from April 22, 2021, through March 31, 2022, and included 11 CCCs in 2 cities. A subset (surveillance group) of CCPs and students participated in active surveillance (weekly reverse transcription-polymerase chain reaction [RT-PCR] swabs, symptom diaries, and optional baseline and end-of-study SARS-CoV-2 serologic testing), as well as all household contacts of surveillance students. Child care center directors reported weekly deidentified self-reported COVID-19 cases from all CCPs and students (self-report group)., Exposure: SARS-CoV-2 infection in CCC students., Main Outcomes and Measures: SARS-CoV-2 incidence, secondary attack rates, and transmission patterns were determined from diary entries, self-reports to CCC directors, and case logs. Incidence rate ratios were measured using Poisson regression clustering on centers with a random intercept and unstructured matrix., Results: From a total population of 1154 students and 402 CCPs who self-reported cases to center directors, 83 students (7.2%; mean [SD] age, 3.86 [1.64] years; 55 male [66%]), their 134 household contacts (118 adults [mean (SD) age, 38.39 (5.07) years; 62 female (53%)], 16 children [mean (SD) age, 4.73 (3.37) years; 8 female (50%)]), and 21 CCPs (5.2%; mean [SD] age, 38.5 [12.9] years; 18 female [86%]) participated in weekly active surveillance. There were 154 student cases (13%) and 87 CCP cases (22%), as defined by positive SARS-CoV-2 RT-PCR or home antigen results. Surveillance students had a higher incidence rate than self-report students (incidence rate ratio, 1.9; 95% CI, 1.1-3.3; P = .01). Students were more likely than CCPs to have asymptomatic infection (34% vs 8%, P < .001). The CCC secondary attack rate was 2.7% to 3.0%, with the upper range representing possible but not definite secondary cases. Whether the index case was a student or CCP, transmission within the CCC was not significantly different. Household cumulative incidence was 20.5%, with no significant difference in incidence rate ratio between adults and children. Household secondary attack rates were 50% for children and 67% for adults. Of 30 household cases, only 5 (17%) represented secondary infections caused by 3 students who acquired SARS-CoV-2 from their CCC. Pre- and poststudy seroprevalence rates were 3% and 22%, respectively, with 90% concordance with antigen or RT-PCR results., Conclusions and Relevance: In this study of SARS-CoV-2 incidence and transmission in CCCs and students' households, transmission within CCCs and from children infected at CCCs into households was low. These findings suggest that current testing and exclusion recommendations for SARS-CoV-2 in CCCs should be aligned with those for other respiratory viruses with similar morbidity and greater transmission to households.

Background: Exposure to per- and polyfluoroalkyl substances (PFAS) has been linked to lower vaccine-induced antibody concentrations in children, while data from adults remains limited and equivocal. Characteristics of PFAS exposure and age at vaccination may modify such effects., Objective: We used the mass administration of novel COVID-19 vaccines to test the hypothesis that prior exposure to environmentally-relevant concentrations of PFAS affect antibody response to vaccines in adolescents and adults., Methods: Between April and June 2021, 226 participants aged 12-90 years with a history of exposure to PFAS in drinking water and who received an mRNA COVID-19 vaccine participated in our prospective cohort study. SARS-CoV-2 anti-spike and anti-nucleocapsid antibodies (IgG) were quantified before the first and second vaccine doses and again at two follow-ups in the following months (up to 103 days post dose 1). Serum PFAS concentrations (n = 39 individual PFAS) were measured once for each participant during baseline, before their first vaccination. The association between PFAS exposure and immune response to vaccination was investigated using linear regression and generalized estimating equation (GEE) models with adjustment for covariates that affect antibody response. PFAS mixture effects were assessed using weighted quantile sum and Bayesian kernel machine regression methods., Results: The geometric mean (standard deviation) of perfluorooctane sulfonate and perfluorooctanoic acid serum concentrations in this population was 10.49 (3.22) and 3.90 (4.90) µg/L, respectively. PFAS concentrations were not associated with peak anti-spike antibody response, the initial increase in anti-spike antibody response following vaccination, or the waning over time of the anti-spike antibody response. Neither individual PFAS concentrations nor their evaluation as a mixture was associated with antibody response to mRNA vaccination against COVID-19., Impact Statement: Given the importance of understanding vaccine response among populations exposed to environmental contaminants and the current gaps in understanding this relationship outside of early life/childhood vaccinations, our manuscript contributes meaningful data from an adolescent and adult population receiving a novel vaccination., (© 2023. The Author(s).)

Introduction: Understanding the changing epidemiology of adults hospitalized with coronavirus disease 2019 (COVID-19) informs research priorities and public health policies., Methods: Among adults (≥18 years) hospitalized with laboratory-confirmed, acute COVID-19 between 11 March 2021, and 31 August 2022 at 21 hospitals in 18 states, those hospitalized during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron-predominant period (BA.1, BA.2, BA.4/BA.5) were compared to those from earlier Alpha- and Delta-predominant periods. Demographic characteristics, biomarkers within 24 hours of admission, and outcomes, including oxygen support and death, were assessed., Results: Among 9825 patients, median (interquartile range [IQR]) age was 60 years (47-72), 47% were women, and 21% non-Hispanic Black. From the Alpha-predominant period (Mar-Jul 2021; N = 1312) to the Omicron BA.4/BA.5 sublineage-predominant period (Jun-Aug 2022; N = 1307): the percentage of patients who had ≥4 categories of underlying medical conditions increased from 11% to 21%; those vaccinated with at least a primary COVID-19 vaccine series increased from 7% to 67%; those ≥75 years old increased from 11% to 33%; those who did not receive any supplemental oxygen increased from 18% to 42%. Median (IQR) highest C-reactive protein and D-dimer concentration decreased from 42.0 mg/L (9.9-122.0) to 11.5 mg/L (2.7-42.8) and 3.1 mcg/mL (0.8-640.0) to 1.0 mcg/mL (0.5-2.2), respectively. In-hospital death peaked at 12% in the Delta-predominant period and declined to 4% during the BA.4/BA.5-predominant period., Conclusions: Compared to adults hospitalized during early COVID-19 variant periods, those hospitalized during Omicron-variant COVID-19 were older, had multiple co-morbidities, were more likely to be vaccinated, and less likely to experience severe respiratory disease, systemic inflammation, coagulopathy, and death., Competing Interests: Potential conflicts of interest. J. C. reports grants from the National Institutes of Health (NIH) and Department of Defense (DoD), outside the submitted work. J. C. reports receiving grants from the NIH, DoD, outside the submitted work. A. D, reports grants from the NIH and National Heart, Lung, and Blood Institute (NHLBI) for the Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV) platform and Prevention and Early Treatment of Acute Lung Injury (PETAL) network respectively, as well as consulting fees for Alung Technologies, outside the submitted work. S. C. reports receiving consulting fees from PureTech Health and Kiniksa Pharmaceuticals and participating as a Data and Safety Monitoring Board (DSMB) member for a neuromodulation study at University of California, Los Angeles, outside the submitted work. M. E. reports grants from NIH and Regeneron, personal funds for speaking at the ASPEN conference for Abbott Labs, and payment for testimony from Medical Legal Expert Witness, outside the submitted work. M. G. reports receiving grants from CDC, CDC-Abt Associates, CDC-Westat, and Janssen, and served as co-chair of the Infectious Diseases and Immunization Committee for the Texas Pediatric Society, outside the submitted work. K. G. reports grants from NIH and DoD, outside the submitted work. A. G. reports receiving grants from NIH, DoD, AbbVie, and Faron Pharmaceuticals, outside the submitted work. M. N. G. reports grants from NHLBI, CDC, Agency for Healthcare Research and Quality (AHRQ), speaking at medicine grand rounds at New York Medical College, travel support for the American Thoracic Society (ATS) executive meeting and serving as ATS Chair Critical Care Assembly, DSMB membership fees from Regeneron, and participating on the scientific advisory panel for Endpoint, outside the submitted work. D. H. reports receiving grants from NHLBI, outside the submitted work. A. K. reports receiving grants from United Therapeutics, Johnson & Johnson, 4D Medical, Eli Lily, Dompe Pharmaceuticals, and GlaxoSmithKline; and serves on the guidelines committee for Chest, outside the submitted work. J. K. reports a grant from NIH, outside the submitted work A. L. reports receiving grants from CDC, National Institute of Allergy and Infectious Diseases (NIAID), and Burroughs Wellcome Fund, Michigan Department of Health and Human Services, Flu Lab, and consulting fees from Sanofi and Roche for consulting on oseltamivir and baloxavir respectively, outside the submitted work. E. M. reports grants from Flu Lab, Merck, and NIH outside the submitted work. T. N. reports receiving a grant from CDC, receiving a one-time payment for participating as a virtual webinar panelist for Clinical Updates in Heart Failure, and being a Practice Management Committee member for Society of Hospital Medicine, outside the submitted work. I. D, P. reports grants from NIH/NHLBI, Janssen Pharmaceuticals and institutional support from Regeneron, outside the submitted work. J. S. reports a grant from NHLBI, outside the submitted work. W. B. S, reports grants from NIH/NHLBI, outside the submitted work. J. W. reports a grant from NIH/NHLBI, payment for the American College of Emergency Physicians speaker honorarium and participating on the American Board of Internal Medicine Critical Care Exam Committee, outside the submitted work. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (Published by Oxford University Press on behalf of Infectious Diseases Society of America 2023.)

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomic and subgenomic RNA levels are frequently used as a correlate of infectiousness. The impact of host factors and SARS-CoV-2 lineage on RNA viral load is unclear., Methods: Total nucleocapsid (N) and subgenomic N (sgN) RNA levels were measured by quantitative reverse transcription polymerase chain reaction (RT-qPCR) in specimens from 3204 individuals hospitalized with coronavirus disease 2019 (COVID-19) at 21 hospitals. RT-qPCR cycle threshold (Ct) values were used to estimate RNA viral load. The impact of time of sampling, SARS-CoV-2 variant, age, comorbidities, vaccination, and immune status on N and sgN Ct values were evaluated using multiple linear regression., Results: Mean Ct values at presentation for N were 24.14 (SD 4.53) for non-variants of concern, 25.15 (SD 4.33) for Alpha, 25.31 (SD 4.50) for Delta, and 26.26 (SD 4.42) for Omicron. N and sgN RNA levels varied with time since symptom onset and infecting variant but not with age, comorbidity, immune status, or vaccination. When normalized to total N RNA, sgN levels were similar across all variants., Conclusions: RNA viral loads were similar among hospitalized adults, irrespective of infecting variant and known risk factors for severe COVID-19. Total N and subgenomic RNA N viral loads were highly correlated, suggesting that subgenomic RNA measurements add little information for the purposes of estimating infectivity., Competing Interests: Potential conflicts of interest. J. Ca. reports grants from National Institutes of Health (NIH) and Department of Defense (DoD), outside the submitted work. J. Ch. reports grants from the NIH, DoD, and Dolly Parton COVID-19 Research Fund, outside the submitted work. D. D. reports a grant from NIH, outside the submitted work. A. D. reports grants from the NIH and National Heart, Lung, and Blood Institute (NHLBI) for the ACTIV platform and PETAL network, respectively; and consulting fees for Alung Technologies, outside the submitted work. M. E. reports grants from NIH and Regeneron; personal funds for speaking at the ASPEN conference for Abbott Labs; and payment for testimony from Medical Legal Expert Witness, outside the submitted work. A. F. reports grants from NIH, outside the submitted work. M. G. reports grants from CDC, CDC-Abt Associates, and CDC-Westat; and served as cochair of the Infectious Diseases and Immunization Committee for the Texas Pediatric Society, outside the submitted work. K. G. reports grants from NIH and DoD; and support for MHSRS 2022 travel from the DoD, outside the submitted work. A. G. reports grants from NIH, DoD, AbbVie, and Faron Pharmaceuticals, outside the submitted work. M. N. G. reports grants from NHLBI, CDC, and Agency for Healthcare Research and Quality; speaking at medicine grand rounds at New York Medical College; travel support for the American Thoracic Society (ATS) executive meeting and serving as ATS Chair Critical Care Assembly; data and safety monitoring board (DSMB) membership fees from Regeneron; and participating on the scientific advisory panel for Endpoint, outside the submitted work. C. G. reports grants from NIH, CDC, AHRQ, FDA, and Campbell Alliance/Syneos Health; and consulting fees from and participating on a DSMB for Merck, outside the submitted work. D. H. reports grants from NHLBI, outside the submitted work. N. H. reports grants from Sandofi and Quidel; and a Genentech educational grant to give a lecture, outside the submitted work. A. K. reports grants from United Therapeutics, Johnson & Johnson, 4D Medical, Eli Lily, Dompe Pharmaceuticals, and GlaxoSmithKline; and serves on the guidelines committee for Chest, outside the submitted work. A. L. reports grants from CDC, National Institute of Allergy and Infectious Diseases, and Burroughs Wellcome Fund; and consulting fees from Sanofi and Roche for consulting on oseltamivir and baloxavir, respectively, outside the submitted work. E. M. reports grants from Flu Lab, Merck, and NIH outside the submitted work. T. M. reports a grant from CDC; a one-time payment for participating as a virtual webinar panelist for Clinical Updates in Heart Failure; and being a Practice Management Committee member for Society of Hospital Medicine, outside the submitted work. I. D. P. reports grants from NIH and Janssen Pharmaceuticals; and institutional support from Asahi Kasei Pharma and Regeneron, outside the submitted work. W. B. S. reports grants and support for meetings/travel from the NIH/NHLBI, outside the submitted work. J. W. reports payment for the American College of Emergency Physicians speaker honorarium and participating on the American Board of Internal Medicine Critical Care Exam Committee, outside the submitted work. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Accurate determination of COVID-19 vaccination status is necessary to produce reliable COVID-19 vaccine effectiveness (VE) estimates. Data comparing differences in COVID-19 VE by vaccination sources (i.e., immunization information systems [IIS], electronic medical records [EMR], and self-report) are limited. We compared the number of mRNA COVID-19 vaccine doses identified by each of these sources to assess agreement as well as differences in VE estimates using vaccination data from each individual source and vaccination data adjudicated from all sources combined., Methods: Adults aged ≥18 years who were hospitalized with COVID-like illness at 21 hospitals in 18 U.S. states participating in the IVY Network during February 1-August 31, 2022, were enrolled. Numbers of COVID-19 vaccine doses identified by IIS, EMR, and self-report were compared in kappa agreement analyses. Effectiveness of mRNA COVID-19 vaccines against COVID-19-associated hospitalization was estimated using multivariable logistic regression models to compare the odds of COVID-19 vaccination between SARS-CoV-2-positive case-patients and SARS-CoV-2-negative control-patients. VE was estimated using each source of vaccination data separately and all sources combined., Results: A total of 4499 patients were included. Patients with ≥1 mRNA COVID-19 vaccine dose were identified most frequently by self-report (n = 3570, 79 %), followed by IIS (n = 3272, 73 %) and EMR (n = 3057, 68 %). Agreement was highest between IIS and self-report for 4 doses with a kappa of 0.77 (95 % CI = 0.73-0.81). VE point estimates of 3 doses against COVID-19 hospitalization were substantially lower when using vaccination data from EMR only (VE = 31 %, 95 % CI = 16 %-43 %) than when using all sources combined (VE = 53 %, 95 % CI = 41 %-62%)., Conclusion: Vaccination data from EMR only may substantially underestimate COVID-19 VE., Competing Interests: Declaration of Competing Interest All authors have completed and submitted the International Committee of Medical Journal Editors (ICJME) disclosure form. Funding for this work was provided to all participating sites by the United States Centers for Disease Control and Prevention. The authors declare the following financial interests/personal relationships, which may be considered as potential competing interests: Samuel Brown reports institutional funds from Janssen for influenza research. Jonathan Casey reports a travel grant from Fischer and Paykel, outside the submitted work. Steven Chang reports consulting fees from PureTech Health and Kiniksa Pharmaceuticals and participating as a DSMB member for a study at UCLA, outside the submitted work. Manjusha Gaglani reports grants from CDC, CDC-Abt Associates, CDC-Westat, and Janssen, and served as co-chair of the Infectious Diseases and Immunization Committee for the Texas Pediatric Society, outside the submitted work. Kevin Gibbs reports grants from NIH and DoD, as well as support for MHSRS 2022 travel from the DoD, outside the submitted work. Adit Ginde reports receiving grants from NIH, DoD, AbbVie, and Faron Pharmaceuticals, outside the submitted work. Michelle N. Gong reports grants from NHLBI, CDC, AHRQ, speaking at medicine grand rounds at New York Medical College, travel support for the ATS executive meeting and serving as ATS Chair Critical Care Assembly, DSMB membership fees from Regeneron, and participating on the scientific advisory panel for Endpoint, outside the submitted work. Carlos Grijalva reports grants from NIH, CDC, AHRQ, FDA, Campbell Alliance/Syneos Health; receiving consulting fees from and participating on a DSMB for Merck, outside the submitted work. David Hager reports receiving grants from NIH, outside the submitted work. Akram Khan reports receiving grants from United Therapeutics, Johnson & Johnson, 4D Medical, Eli Lily, Dompe Pharmaceuticals, and GlaxoSmithKline; and serves on the guidelines committee for Chest, outside the submitted work. Adam Lauring reports receiving grants from CDC, FluLab, NIAID, and Burroughs Wellcome Fund, and consulting fees from Sanofi and Roche for consulting on oseltamivir and baloxavir respectively, outside the submitted work. Emily Martin reports grants from Merck and NIH, outside the submitted work. Tresa McNeal reports receiving a grant from CDC, receiving a one-time payment for participating as a virtual webinar panelist for Clinical Updates in Heart Failure, and being a Practice Management Committee member for Society of Hospital Medicine, outside the submitted work. Ithan D. Peltan reports grants from NIH, Janssen Pharmaceuticals and institutional support from Asahi Kasei Pharma and Regeneron, outside the submitted work. Jennifer Wilson reports grants from NHLBI, outside the submitted work. No other potential conflicts of interest were disclosed., (Published by Elsevier Ltd.)

Background: We estimated combined protection conferred by prior SARS-CoV-2 infection and COVID-19 vaccination against COVID-19-associated acute respiratory illness (ARI)., Methods: During SARS-CoV-2 Delta (B.1.617.2) and Omicron (B.1.1.529) variant circulation between October 2021 and April 2022, prospectively enrolled adult patients with outpatient ARI had respiratory and filter paper blood specimens collected for SARS-CoV-2 molecular testing and serology. Dried blood spots were tested for immunoglobulin-G antibodies against SARS-CoV-2 nucleocapsid (NP) and spike protein receptor binding domain antigen using a validated multiplex bead assay. Evidence of prior SARS-CoV-2 infection also included documented or self-reported laboratory-confirmed COVID-19. We used documented COVID-19 vaccination status to estimate vaccine effectiveness (VE) by multivariable logistic regression by prior infection status., Results: Four hundred fifty-five (29%) of 1577 participants tested positive for SARS-CoV-2 infection at enrollment; 209 (46%) case-patients and 637 (57%) test-negative patients were NP seropositive, had documented previous laboratory-confirmed COVID-19, or self-reported prior infection. Among previously uninfected patients, three-dose VE was 97% (95% confidence interval [CI], 60%-99%) against Delta, but not statistically significant against Omicron. Among previously infected patients, three-dose VE was 57% (CI, 20%-76%) against Omicron; VE against Delta could not be estimated., Conclusions: Three mRNA COVID-19 vaccine doses provided additional protection against SARS-CoV-2 Omicron variant-associated illness among previously infected participants., (© 2023 The Authors. Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

As of April 2023, the COVID-19 pandemic has resulted in 1.1 million deaths in the United States, with approximately 75% of deaths occurring among adults aged ≥65 years (1). Data on the durability of protection provided by monovalent mRNA COVID-19 vaccination against critical outcomes of COVID-19 are limited beyond the Omicron BA.1 lineage period (December 26, 2021-March 26, 2022). In this case-control analysis, the effectiveness of 2-4 monovalent mRNA COVID-19 vaccine doses was evaluated against COVID-19-associated invasive mechanical ventilation (IMV) and in-hospital death among immunocompetent adults aged ≥18 years during February 1, 2022-January 31, 2023. Vaccine effectiveness (VE) against IMV and in-hospital death was 62% among adults aged ≥18 years and 69% among those aged ≥65 years. When stratified by time since last dose, VE was 76% at 7-179 days, 54% at 180-364 days, and 56% at ≥365 days. Monovalent mRNA COVID-19 vaccination provided substantial, durable protection against IMV and in-hospital death among adults during the Omicron variant period. All adults should remain up to date with recommended COVID-19 vaccination to prevent critical COVID-19-associated outcomes., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Jonathan D. Casey reports grants from the National Institutes of Health (NIH) and the U.S. Department of Defense (DoD), and a travel grant from Fisher and Paykel, outside the submitted work. Steven Y. Chang reports consulting fees from PureTech Health and Kiniksa Pharmaceuticals, and participation as a Data Safety Monitoring Board (DSMB) member for a study at UCLA, outside the submitted work. Abhijit Duggal reports grants from NIH/National Heart, Lung, and Blood Institute (NHLBI), and consulting fees from Alung Technologies, outside the submitted work. David J. Douin reports a grant from NIH/National Institute of General Medical Sciences, outside the submitted work. Matthew C. Exline reports grants from NIH and Regeneron, honoria for speaking at the American Society for Parenteral and Enteral Nutrition conference from Abbott Labs, and payment for testimony as a medical legal expert witness, outside the submitted work. D. Clark Files reports receiving a grant from NIH and participating on the Medpace DSMB, outside the submitted work. Manjusha Gaglani reports having served as co-chair of the Infectious Diseases and Immunization Committee for the Texas Pediatric Society, outside the submitted work. Kevin W. Gibbs reports grants from NIH and DoD, as well as support for travel to the 2022 Military Health System Research Symposium from DoD, outside the submitted work. Adit A. Ginde reports receiving grants from NIH, DoD, AbbVie, and Faron Pharmaceuticals, outside the submitted work. Michelle N. Gong reports grants from NHLBI, the Agency for Healthcare Research and Quality (AHRQ), speaking at medicine grand rounds at Yale and Westchester Medical College, travel support from the American Thoracic Society (ATS) and serving on the ATS board, DSMB membership fees from Regeneron and the Replenish Trial, and participating on the scientific advisory panel for Endpoint, outside the submitted work. Carlos G. Grijalva reports grants from NIH, AHRQ, the Food and Drug Administration (FDA), Campbell Alliance/Syneos Health; receipt of consulting fees from and participation on a DSMB for Merck, outside the submitted work. David N. Hager reports receiving grants from NIH, outside the submitted work. Natasha Halasa reports receiving grants from Sanofi and Quidel, outside the submitted work. Akram Khan reports receiving grants from United Therapeutics, Johnson & Johnson, 4D Medical, Eli Lily, Dompe Pharmaceuticals, and GlaxoSmithKline; and serves on the guidelines committee for Chest, outside the submitted work. Adam S. Lauring reports receiving grants from FluLab, NIH/National Institute of Allergy and Infectious Diseases, and Burroughs Wellcome Fund, and consulting fees from Sanofi and Roche for consulting on oseltamivir and baloxavir respectively, outside the submitted work. Emily T. Martin reports grants from Merck and NIH, outside the submitted work. Tresa McNeal reports receiving a one-time payment for participating as a virtual webinar panelist for Clinical Updates in Heart Failure, and being a Practice Management Committee member for Society of Hospital Medicine, outside the submitted work. Arnold S. Monto reports a grant from NIH/NIAID, support for travel from the International Society for Influenza and other Respiratory Diseases, and participation on an advisory board for FDA, outside the submitted work. Ithan D. Peltan reports grants from NIH and Janssen Pharmaceuticals and institutional support from Asahi Kasei Pharma and Regeneron, outside the submitted work. Jay S. Steingrub reports a grant from NHLBI, outside the submitted work. Jennifer G. Wilson reports grants from NHLBI, outside the submitted work. No other potential conflicts of interest were disclosed.

Background: In the United States, influenza activity during the 2021-2022 season was modest and sufficient enough to estimate influenza vaccine effectiveness (VE) for the first time since the beginning of the coronavirus disease 2019 pandemic. We estimated influenza VE against laboratory-confirmed outpatient acute illness caused by predominant A(H3N2) viruses., Methods: Between October 2021 and April 2022, research staff across 7 sites enrolled patients aged ≥6 months seeking outpatient care for acute respiratory illness with cough. Using a test-negative design, we assessed VE against influenza A(H3N2). Due to strong correlation between influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination, participants who tested positive for SARS-CoV-2 were excluded from VE estimations. Estimates were adjusted for site, age, month of illness, race/ethnicity, and general health status., Results: Among 6260 participants, 468 (7%) tested positive for influenza only, including 440 (94%) for A(H3N2). All 206 sequenced A(H3N2) viruses were characterized as belonging to genetic group 3C.2a1b subclade 2a.2, which has antigenic differences from the 2021-2022 season A(H3N2) vaccine component that belongs to clade 3C.2a1b subclade 2a.1. After excluding 1948 SARS-CoV-2-positive patients, 4312 patients were included in analyses of influenza VE; 2463 (57%) were vaccinated against influenza. Effectiveness against A(H3N2) for all ages was 36% (95% confidence interval, 20%-49%) overall., Conclusions: Influenza vaccination in 2021-2022 provided protection against influenza A(H3N2)-related outpatient visits among young persons., Competing Interests: Potential conflicts of interest. A. F. reports institutional grant support for research from Gilead, GlaxoSmithKline, Moderna, CDC, and Pfizer, unrelated to this work. C. G. G. reports consulting fees from Merck, Pfizer, and Sanofi Pasteur, and institutional grant support from the Agency for Healthcare Research and Quality, Campbell Alliance/Syneos Health, Food and Drug Administration, CDC, Sanofi, and National Institutes of Health. E. T. M. reports institutional grant support from Merck. A. S. M. reports personal fees from Sanofi and nonfinancial support from Seqirus. M. P. N. reports unrelated institutional grant support and personal fees from Merck Sharp & Dohme and institutional investigator-initiated grant support from Sanofi Pasteur. S. Y. T. reports institutional grant support from Pfizer and GlaxoSmithKline, unrelated to this work. M. G. reports CDC-BSWH US Flu VE Network HAIVEN grant studies, Synergy contract study, CDC-Abt HCP FluVax randomized controlled trial and RECOVER-PROTECT cohort studies, CDC-Vanderbilt IVY-3 and IVY-4 studies, and CDC-Westat VISION COVID/Flu VE Study, unrelated to this work., (Published by Oxford University Press on behalf of Infectious Diseases Society of America 2022.)

Background: The annual reappearance of respiratory viruses has been recognized for decades. COVID-19 mitigation measures taken during the pandemic were targeted at respiratory transmission and broadly impacted the burden of acute respiratory illnesses (ARIs)., Methods: We used the longitudinal Household Influenza Vaccine Evaluation (HIVE) cohort in southeast Michigan to characterize the circulation of respiratory viruses from March 1, 2020, to June 30, 2021, using RT-PCR of respiratory specimens collected at illness onset. Participants were surveyed twice during the study period, and SARS-CoV-2 antibodies were measured in serum by electrochemiluminescence immunoassay. Incidence rates of ARI reports and virus detections were compared between the study period and a preceding pre-pandemic period of similar duration., Results: Overall, 437 participants reported a total of 772 ARIs; 42.6% had respiratory viruses detected. Rhinoviruses were the most frequent virus, but seasonal coronaviruses, excluding SARS-CoV-2, were also common. Illness reports and percent positivity were lowest from May to August 2020, when mitigation measures were most stringent. Seropositivity for SARS-CoV-2 was 5.3% in summer 2020 and increased to 11.3% in spring 2021. The incidence rate of total reported ARIs for the study period was 50% lower (95% CI: 0.5, 0.6; p  < 0.001) than the incidence rate from a pre-pandemic comparison period (March 1, 2016, to June 30, 2017)., Conclusions: The burden of ARI in the HIVE cohort during the COVID-19 pandemic fluctuated, with declines occurring concurrently with the widespread use of public health measures. Rhinovirus and seasonal coronaviruses continued to circulate even when influenza and SARS-CoV-2 circulation was low., Competing Interests: ETM reports grant funding from Merck outside of the submitted work., (© 2023 The Authors. Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd.)

Background: Coronavirus disease 2019 (COVID-19) messenger RNA (mRNA) vaccines were authorized in the United States in December 2020. Although vaccine effectiveness (VE) against mild infection declines markedly after several months, limited understanding exists on the long-term durability of protection against COVID-19-associated hospitalization., Methods: Case-control analysis of adults (≥18 years) hospitalized at 21 hospitals in 18 states 11 March-15 December 2021, including COVID-19 case patients and reverse transcriptase-polymerase chain reaction-negative controls. We included adults who were unvaccinated or vaccinated with 2 doses of a mRNA vaccine before the date of illness onset. VE over time was assessed using logistic regression comparing odds of vaccination in cases versus controls, adjusting for confounders. Models included dichotomous time (<180 vs ≥180 days since dose 2) and continuous time modeled using restricted cubic splines., Results: A total of 10 078 patients were included, 4906 cases (23% vaccinated) and 5172 controls (62% vaccinated). Median age was 60 years (interquartile range, 46-70), 56% were non-Hispanic White, and 81% had ≥1 medical condition. Among immunocompetent adults, VE <180 days was 90% (95% confidence interval [CI], 88-91) versus 82% (95% CI, 79-85) at ≥180 days (P < .001). VE declined for Pfizer-BioNTech (88% to 79%, P < .001) and Moderna (93% to 87%, P < .001) products, for younger adults (18-64 years) (91% to 87%, P = .005), and for adults ≥65 years of age (87% to 78%, P < .001). In models using restricted cubic splines, similar changes were observed., Conclusions: In a period largely predating Omicron variant circulation, effectiveness of 2 mRNA doses against COVID-19-associated hospitalization was largely sustained through 9 months., Competing Interests: Potential conflicts of interest. All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. W. H. S. reports grant funding from the Centers for Disease Control and Prevention (CDC) for this work, grants and consultant fees from Merck (for research on the surveillance of pneumococcal infections) and Gilead Sciences (for research on the surveillance of hepatitis C virus infections) outside this work. M. G. reports grant support from CDC (Ambulatory US Flu/COVID VE Network and Adult Inpatient Flu/COVID VE Network, HAIVEN), CDC-Abt Associates (Flu Vax Immunogenitiy RCT and RECVOERPROTECT COVID/Flu VE studies), CDC-Westat (VISION COVID Study), and Janssen (Johnson & Johnson) (RSV Severity App Birth Cohort Study). A. A. G. reports grant support from CDC, National Institute of Health (NIH), Department of Defense (DoD), AbbVie, and Faron Pharmaceuticals. J. D. C. reports grants from the CDC, NIH (K23HL153584), and Department of Defense. N. M. reports grants from the CDC (funded two other multicenter COVID-related projects separate from this work through payments to my institution). T. M. reports a grant from CDC and fees from the Society of Hospital Medicine for a talk about managing patients with congestive heart failure. K. G. reports grants from the CDC and the received grant funding for participation in executive committee of COVID-19 therapeutics from the NIH (ACTIV-4HT NECTAR Trial). D. C. F. reports grant support from CDC, consultant fees from Cytovale, and membership on a Medpace Data Safety Monitoring Board (DSMB). D. N. H. reports contracts from CDC, National Heart, Lung, and Blood Institute (NHLBI; funding for participation in the ACTIV4d - Host Tissue Trial), and Incyte Corporation (funding to enroll in RUCOVID-DEVENT) and membership on the SAFE EVICT Trial of VIT C in COVID-19 as DSMB chair. M. C. E. reports talks on nutrition in COVID pneumonia at the American Society of Parenteral and Enteral Nutrition (ASPEN) conference sponsored by Abbott Labs. M. N. G. reports grant support from CDC, NHLBI, NIH, and Agency for Healthcare Research and Quality (AHRQ), travel support for American Thoracic Society board meeting, and membership on the Regeneron DSMB for monoclonal antibodies in COVID-19. N. J. reports grants from CDC, NIH/NHLBI/NINDS, and University of Washington Royalty Research Fund, and payment for expert testimony from the Washington Department of Health. I. D. P. reports grants from CDC, NIH, Intermountain Research & Medical Foundation, and Janssen Pharmaceuticals, and institutional fees from Asahi Kasei Pharma and from Regeneron Pharmaceuticals. S. M. B. reports grants from CDC, NIH (for trials and other research activities related to COVID), and DoD (to study COVID); fees from Hamilton ventilators for chairing a DSMB; and personal fees from New York University for service on a DSMB. E. T. M. reports a grant from Merck outside the submitted work. A. M. reports grant support from CDC, NIH, NIAID, and membership on a DSMB for the Food and Drug Administration (FDA). A. K. reports grants from CDC, Gilead Sciences, Ely Lily, United Therapeutics, BOA-Medical, and 4D Medical and membership on the Guidelines Committee for Chest. C. L. H. reports grants from CDC, NIH, and the American Lung Association. A. D. reports a grant from the CDC and consulting fees from ALung Technologies (Steering Committee). J. W. reports grants from the CDC and NIH (ARREST Pneumonia Trial UH3HL141722, ACTIV3a and 3b trials, and ACTIV4a trial), and membership on the American Board of Internal Medicine Critical Care Medicine exam committee. S. Y. C. reports grants from CDC and Regeneron (for 6R88-COV-2040 trial) and consulting fees from PureTech Health (for COVID study) and Kiniska (for possible ARDS study). J. H. K. reports grant support from CDC and NIH (1K23 AI137321-01A1). A. S. L. reports grants from the CDC, NIH, and Burroughs Wellcome Fund, consultant fees for antiviral drugs from Sanofi and fees from Roche for membership on a baloxavir trial steering committee. N. H. reports grants from CDC, NIH, Sanofi, and Quidel and honoraria for speaking at a continuing medical education event at American Academy of Pediatrics. C. G. G. reports consultant fees from Pfizer, Merck, and Sanofi and grants from Syneos Health, CDC, NIH, FDA, AHRQ, and Sanofi. T. R. reports grants from CDC and Abbvie Inc, consultant fees from Cytovale, Inc. and Cumberland Pharmaceuticals Inc., membership on a Sanofi, Inc. DSMB, a voluntary role as the Immediate Past President of ASPEN and stock in Cumberland Pharmaceuticals, Inc. I. J. reports grants/contracts from the CDC, NIH, Quidel, and Sanofi. C. J. L. reports grants/contracts from CDC, NIH, DoD, bioMerieux, Endpoint Health, Entegrion, Inc., and AbbVie; a patent issued to Cincinnati Children’s Hospital Medical Center for risk stratification in sepsis and septic shock, membership on a Study Principal Investigators DSMB for clinical trials unrelated to the current work, Executive Committee; Immediate Past President, Member, Board of Directors, Association for Clinical and Translational Science, and stock options in Bioscape Digita unrelated to the current work. W. B. S. reports a grant from the CDC and NIH (5K12HL133117-05). All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2022.)

Persons with COVID-19-like illnesses are advised to stay home to reduce the spread of SARS-CoV-2. We assessed relationships between telework experience and COVID-19 illness with work attendance when ill. Adults experiencing fever, cough, or loss of taste or smell who sought healthcare or COVID-19 testing in the United States during March-November 2020 were enrolled. Adults with telework experience before illness were more likely to work at all (onsite or remotely) during illness (87.8%) than those with no telework experience (49.9%) (adjusted odds ratio 5.48, 95% CI 3.40-8.83). COVID-19 case-patients were less likely to work onsite (22.1%) than were persons with other acute respiratory illnesses (37.3%) (adjusted odds ratio 0.36, 95% CI 0.24-0.53). Among COVID-19 case-patients with telework experience, only 6.5% worked onsite during illness. Telework experience before illness gave mildly ill workers the option to work and improved compliance with public health recommendations to stay home during illness.

Transmission bottlenecks limit the spread of novel mutations and reduce the efficiency of selection along a transmission chain. While increased force of infection, receptor binding, or immune evasion may influence bottleneck size, the relationship between transmissibility and the transmission bottleneck is unclear. Here we compare the transmission bottleneck of non-VOC SARS-CoV-2 lineages to those of Alpha, Delta, and Omicron. We sequenced viruses from 168 individuals in 65 households. Most virus populations had 0-1 single nucleotide variants (iSNV). From 64 transmission pairs with detectable iSNV, we identify a per clade bottleneck of 1 (95% CI 1-1) for Alpha, Delta, and Omicron and 2 (95% CI 2-2) for non-VOC. These tight bottlenecks reflect the low diversity at the time of transmission, which may be more pronounced in rapidly transmissible variants. Tight bottlenecks will limit the development of highly mutated VOC in transmission chains, adding to the evidence that selection over prolonged infections may drive their evolution., (© 2023. The Author(s).)

Monovalent COVID-19 mRNA vaccines, designed against the ancestral strain of SARS-CoV-2, successfully reduced COVID-19-related morbidity and mortality in the United States and globally (1,2). However, vaccine effectiveness (VE) against COVID-19-associated hospitalization has declined over time, likely related to a combination of factors, including waning immunity and, with the emergence of the Omicron variant and its sublineages, immune evasion (3). To address these factors, on September 1, 2022, the Advisory Committee on Immunization Practices recommended a bivalent COVID-19 mRNA booster (bivalent booster) dose, developed against the spike protein from ancestral SARS-CoV-2 and Omicron BA.4/BA.5 sublineages, for persons who had completed at least a primary COVID-19 vaccination series (with or without monovalent booster doses) ≥2 months earlier (4). Data on the effectiveness of a bivalent booster dose against COVID-19 hospitalization in the United States are lacking, including among older adults, who are at highest risk for severe COVID-19-associated illness. During September 8-November 30, 2022, the Investigating Respiratory Viruses in the Acutely Ill (IVY) Network § assessed effectiveness of a bivalent booster dose received after ≥2 doses of monovalent mRNA vaccine against COVID-19-associated hospitalization among immunocompetent adults aged ≥65 years. When compared with unvaccinated persons, VE of a bivalent booster dose received ≥7 days before illness onset (median = 29 days) against COVID-19-associated hospitalization was 84%. Compared with persons who received ≥2 monovalent-only mRNA vaccine doses, relative VE of a bivalent booster dose was 73%. These early findings show that a bivalent booster dose provided strong protection against COVID-19-associated hospitalization in older adults and additional protection among persons with previous monovalent-only mRNA vaccination. All eligible persons, especially adults aged ≥65 years, should receive a bivalent booster dose to maximize protection against COVID-19 hospitalization this winter season. Additional strategies to prevent respiratory illness, such as masking in indoor public spaces, should also be considered, especially in areas where COVID-19 community levels are high (4,5)., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Samuel M. Brown reports serving as the data and safety monitoring board (DSMB) chair for Hamilton Ventilators outside the submitted work. Jonathan D. Casey reports grants from the National Institutes of Health (NIH) and Department of Defense (DoD), outside the submitted work. Steven Y. Chang consulted for PureTech Health in 2020 and Kiniksa Pharmaceuticals and is a DSMB member for an investigator-initiated study at UCLA. James D. Chappell reports grants from NIH and DoD during the conduct of the study. Cristie Columbus reports support from Baylor University Medical Center for meeting attendance, an advisory role to the Dallas County Public Health Committee, and other interests as the Chief of the Division of Infectious Diseases at Baylor University Medical Center and the Medical Director for Infection Prevention and Control/Healthcare epidemiology, outside the submitted work. David J. Douin reports grants received from NIH and the National Institute of General Medical Sciences, outside the submitted work. Abhijit Duggal reports grants from NIH and the National Heart, Lung, and Blood Institute (NHLBI), and participation on a Steering Committee for ALung technologies, outside the submitted work. Matthew C. Exline reports grants from NIH and Regeneron, as well as support from Abbott Labs and Medical Legal Expert Witness for sponsored talks, outside the submitted work. D. Clark Files reports personal consultant fees from Global Blood Therapeutics and is a DSMB member from Medpace, outside the submitted work. Manjusha Gaglani reports grants from CDC-Abt Associates, CDC-Westat, and Janssen, and participates as co-chair on the Infection Diseases and Immunizations Committee for the Texas Pediatric Society, outside the submitted work. Kevin W. Gibbs reports grants from NIH and DoD, and DoD funds for the Military Health System Research Symposium travel in 2022, outside the submitted work. Adit A. Ginde reports grants from NIH, DoD, AbbVie, and Faron Pharmaceuticals, outside the submitted work. Michelle N. Gong reports grants from NHLBI and the Agency for Healthcare Research and Quality (AHRQ), speaking at medicine grand rounds at New York Medical College, travel support for the American Thoracic Society (ATS) executive meeting and serving as ATS Chair Critical Care Assembly, DSMB membership fees from Regeneron, and participating on the scientific advisory panel for Endpoint, outside the submitted work. Carlos G. Grijalva reports consultancy fees from Merck; grants from Campbell Alliance/Syneos Health, NIH, the Food and Drug Administration, and AHRQ outside the submitted work. David N. Hager reports grants from NHLBI outside the submitted work. Natasha Halasa reports grants and nonfinancial support from Sanofi, and grants from Quidel outside the submitted work. Nicholas J. Johnson reports grants from NIH, DoD, University of Washington, and Medic One Foundation, outside the submitted work. Akram Khan reports grants from United Therapeutics, Johnson & Johnson, Ely Lilly, 4D Medical, Dompe Pharmaceuticals and GlaxoSmithKline, and serves on the Guidelines committee for Chest, outside the submitted work. Jennie H. Kwon reports grants from NIH outside the submitted work. Adam S. Lauring reports personal fees from Sanofi and Roche and grants from the National Institute for Allergy and Infectious Diseases, Burroughs Wellcome Fund, Flu Lab, outside the submitted work. Emily T. Martin reports grants from Merck, Flu Lab, and NIH, outside the submitted work. Tresa McNeal reports grants from participating as a webinar invited panelist and a Practice Management Committee member for Society of Hospital Medicine, outside the submitted work. Ithan D. Peltan reports grants from NIH, Janssen Pharmaceuticals, and institutional support from Asahi Kasei Pharma and Regeneron, outside the submitted work. Todd W. Rice reports grants from NIH and DoD, personal fees from Cumberland Pharmaceuticals, Inc., Cytovale, Inc., and Sanofi, Inc., outside the submitted work. William B. Stubblefield reports grants from NIH outside the submitted work. Jennifer G. Wilson reports personal funds from the American College of Emergency Physicians and American Board of Internal Medicine outside the submitted work. No other potential conflicts of interest were disclosed.

When first approved, many hoped that the SARS-CoV-2 vaccine would provide long-term protection after a primary series. Waning of immunity and continued appearance of new variants has made booster inoculations necessary. The process is becoming increasingly similar to that used for annual updating of the influenza vaccine. The similarity has become even more apparent with selection of BA.4/BA.5 as the Omicron strain of the updated bivalent (Original + Omicron) COVID-19 vaccines. It is hoped that, if COVID-19 develops winter seasonality, SARS-CoV-2 vaccines will require only annual review to determine if updates are necessary. Recommendations on whom should receive the booster would be based on conditions at that time., Competing Interests: Potential conflicts of interest . E. T. M. reports receiving grant support from Merck. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Test-negative design (TND) studies have produced validated estimates of vaccine effectiveness (VE) for influenza vaccine studies. However, syndrome-negative controls have been proposed for differentiating bias and true estimates in VE evaluations for COVID-19. To understand the use of alternative control groups, we compared characteristics and VE estimates of syndrome-negative and test-negative VE controls., Methods: Adults hospitalized at 21 medical centers in 18 states March 11-August 31, 2021 were eligible for analysis. Case patients had symptomatic acute respiratory infection (ARI) and tested positive for SARS-CoV-2. Control groups were test-negative patients with ARI but negative SARS-CoV-2 testing, and syndrome-negative controls were without ARI and negative SARS-CoV-2 testing. Chi square and Wilcoxon rank sum tests were used to detect differences in baseline characteristics. VE against COVID-19 hospitalization was calculated using logistic regression comparing adjusted odds of prior mRNA vaccination between cases hospitalized with COVID-19 and each control group., Results: 5811 adults (2726 cases, 1696 test-negative controls, and 1389 syndrome-negative controls) were included. Control groups differed across characteristics including age, race/ethnicity, employment, previous hospitalizations, medical conditions, and immunosuppression. However, control-group-specific VE estimates were very similar. Among immunocompetent patients aged 18-64 years, VE was 93 % (95 % CI: 90-94) using syndrome-negative controls and 91 % (95 % CI: 88-93) using test-negative controls., Conclusions: Despite demographic and clinical differences between control groups, the use of either control group produced similar VE estimates across age groups and immunosuppression status. These findings support the use of test-negative controls and increase confidence in COVID-19 VE estimates produced by test-negative design studies., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: All authors have completed and submitted the International Committee of Medical Journal Editors (ICMJE) disclosure form. Funding for this work was provided to all participating sites by the United States Centers for Disease Control and Prevention. Samuel Brown reports grants from National Institutes of Health (NIH) and Department of Defense (DoD), participation as the DSMB chair for Hamilton Ventilators, and participation as a member of the DSMB for New York University COVID clinical trials. Jonathan Casey reports funding from NIH and DoD. Steven Chang reports consulting fees from La Jolla Pharmaceuticals, PureTech Health, and Kiniska Pharmaceuticals, payment/honoraria from La Jolla Pharmaceuticals, and participation on a DSMB for an investigator-initiated study conducted at UCLA. James Chappell reports grants and other support from NIH. Abhijit Duggal reports consulting fees from ALung technologies. Matthew Exline reports payment/honorariua from Abbott Lab for sponsored talks. D. Clark Files reports consulting fees from Cytovale and participation on a DSMB for Medpace. Anne Frosch reports grants from NIH. Manjusha Gaglani reports grants from Centers for Disease Control and Prevention (CDC), CDC-Abt Associates, CDC-Westat, and Janssen, and a leadership role as co-chair of the Infectious Disease and Immunization Committee of the Texas Pediatric Society, Texas Chapter of American Academy of Pediatrics. Kevin Gibbs reports funding from NIH/ National Heart, Lung, and Blood Institute (NHLBI) for the ACTIV-4HT NECTAR trial. Nicholas Mohr reports grants from the CDC (funded 2 other multicenter COVID-related projects separate from this work through payments to author’s institution). Adit Ginde reports grants from NIH, DoD, AbbVie, and Faron Pharmaceuticals. Michelle Gong reports grants from NIH/NHLBI and Agency for Healthcare Research and Quality (AHRQ), consulting fees from Endpoint, a leadership role on the American Thoracic Society (ATS) executive committee and board as well as support from ATS for meeting travel expenses, and participation on a DSMB for Regeneron. Carlos Grijalva reports grants from NIH, CDC, Food and Drug Administration (FDA), AHRQ, Sanofi, and Syneos Health and consulting fees from Pfizer, Merck, and Sanofi. David Hager reports grants from NIH/NHLBI for the ACTIV-4HT NECTAR trial and Incyte Corporation and participation as a DSMB chair for the SAFE EVICT Trial of vitamin C in COVID-19. Jennifer Wilson reports grants from the CDC and NIH (ARREST Pneumonia Trial UH3HL141722, ACTIV3a and 3b trials, and ACTIV4a trial), and membership on the American Board of Internal Medicine Critical Care Medicine exam committee. Natasha Halasa reports grants from NIH, Quidel, and Sanofi and honoraria for speaking at the American Academy of Pediatrics (AAP) conference. Nicholas Johnson reports grants from NIH/NHLBI/NINDS and the University of Washington Royalty Research Fund and payment for expert testimony for the Washington Department of Health. Akram Khan reports grants from United Therapeutics, Gilead Sciences, and 4D Medical and a leadership role on the guidelines committee for Chest. Jennie Kwon reports grants from NIH/NIAID. Adam Lauring reports grants from CDC, NIH/NIAID, and Burroughs Wellcome Fund and consulting fees from Sanofi and Roche. Christopher Lindsell reports grants from NIH, DoD, CDC, bioMerieux, Entegrion Inc., Endpoint Health, and AbbVie, patents for risk stratification in sepsis and septic shock, participation on DSMBs for clinical trials unrelated to the current work, a leadership role on the executive committee for the Board of Directors of the Association for Clinical and Translational Science, and stock options in Bioscape Digita. Emily Martin reports grants from Merck, CDC, and NIH and payment/honoraria from the Michigan Infectious Disease Society. Tresa McNeal reports payment/honoraria from the Society of Hospital Medicine. Ithan Peltan reports grants from NIH, Janssen, Regeneron, and Asahi Kasei Pharma. Todd Rice reports grants from AbbVie Inc., consulting fees from Cumberland Pharmaceuticals, Inc. and Cytovale, Inc., membership on a DSMB for Sanofi, Inc., a leadership role as immediate past president of the American Society of Parenteral and Enteral Nutrition, and stock options in Cumberland Pharmaceuticals, Inc. Wesley Self reports receiving the primary funding for this project from the United States Centers for Disease Control and Prevention, and research funding from Merck and Gilead Sciences. William Stubblefield reports grants from the NIH/NHLBI., (Published by Elsevier Ltd.)

Background: During the COVID-19 pandemic, self-reported COVID-19 vaccination might facilitate rapid evaluations of vaccine effectiveness (VE) when source documentation (e.g., immunization information systems [IIS]) is not readily available. We evaluated the concordance of COVID-19 vaccination status ascertained by self-report versus source documentation and its impact on VE estimates., Methods: Hospitalized adults (≥18 years) admitted to 18 U.S. medical centers March-June 2021 were enrolled, including COVID-19 cases and SARS-CoV-2 negative controls. Patients were interviewed about COVID-19 vaccination. Abstractors simultaneously searched IIS, medical records, and other sources for vaccination information. To compare vaccination status by self-report and documentation, we estimated percent agreement and unweighted kappa with 95% confidence intervals (CIs). We then calculated VE in preventing COVID-19 hospitalization of full vaccination (2 doses of mRNA product ≥14 days prior to illness onset) independently using data from self-report or source documentation., Results: Of 2520 patients, 594 (24%) did not have self-reported vaccination information to assign vaccination group; these patients tended to be more severely ill. Among 1924 patients with both self-report and source documentation information, 95.0% (95% CI: 93.9-95.9%) agreement was observed, with a kappa of 0.9127 (95% CI: 0.9109-0.9145). VE was 86% (95% CI: 81-90%) by self-report data only and 85% (95% CI: 81-89%) by source documentation data only., Conclusions: Approximately one-quarter of hospitalized patients could not provide self-report COVID-19 vaccination status. Among patients with self-report information, there was high concordance with source documented status. Self-report may be a reasonable source of COVID-19 vaccination information for timely VE assessment for public health action., (© 2022 The Authors. Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

Accurate estimates of the total burden of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are needed to inform policy, planning, and response. We sought to quantify SARS-CoV-2 cases, hospitalizations, and deaths by age in Michigan. Coronavirus disease 2019 cases reported to the Michigan Disease Surveillance System were multiplied by age and time-specific adjustment factors to correct for under-detection. Adjustment factors were estimated in a model fit to incidence data and seroprevalence estimates. Age-specific incidence of SARS-CoV-2 hospitalization, death, vaccination, and variant proportions were estimated from publicly available data. We estimated substantial under-detection of infection that varied by age and time. Accounting for under-detection, we estimate the cumulative incidence of infection in Michigan reached 75% by mid-November 2021, and over 87% of Michigan residents were estimated to have had ≥1 vaccination dose and/or previous infection. Comparing pandemic waves, the relative burden among children increased over time. In general, the proportion of cases who were hospitalized or who died decreased over time. Our results highlight the ongoing risk of periods of high SARS-CoV-2 incidence despite widespread prior infection and vaccination. This underscores the need for long-term planning for surveillance, vaccination, and other mitigation measures amidst continued response to the acute pandemic., (© 2022 The Authors. Journal of Medical Virology published by Wiley Periodicals LLC.)

Background: We estimated SARS-CoV-2 Delta- and Omicron-specific effectiveness of two and three mRNA COVID-19 vaccine doses in adults against symptomatic illness in US outpatient settings., Methods: Between October 1, 2021, and February 12, 2022, research staff consented and enrolled eligible participants who had fever, cough, or loss of taste or smell and sought outpatient medical care or clinical SARS-CoV-2 testing within 10 days of illness onset. Using the test-negative design, we compared the odds of receiving two or three mRNA COVID-19 vaccine doses among SARS-CoV-2 cases versus controls using logistic regression. Regression models were adjusted for study site, age, onset week, and prior SARS-CoV-2 infection. Vaccine effectiveness (VE) was calculated as (1 - adjusted odds ratio) × 100%., Results: Among 3847 participants included for analysis, 574 (32%) of 1775 tested positive for SARS-CoV-2 during the Delta predominant period and 1006 (56%) of 1794 participants tested positive during the Omicron predominant period. When Delta predominated, VE against symptomatic illness in outpatient settings was 63% (95% CI: 51% to 72%) among mRNA two-dose recipients and 96% (95% CI: 93% to 98%) for three-dose recipients. When Omicron predominated, VE was 21% (95% CI: -6% to 41%) among two-dose recipients and 62% (95% CI: 48% to 72%) among three-dose recipients., Conclusions: In this adult population, three mRNA COVID-19 vaccine doses provided substantial protection against symptomatic illness in outpatient settings when the Omicron variant became the predominant cause of COVID-19 in the United States. These findings support the recommendation for a third mRNA COVID-19 vaccine dose., Competing Interests: Ana Florea reports unrelated institutional grant support for research from Gilead, GlaxoSmithKline, Moderna, and Pfizer. Carlos G. Grijalva reports consulting fees from Merck, Pfizer, and Sanofi Pasteur, and institutional grant support from the Agency for Health Care Research and Quality, Campbell Alliance/Syneos Health, the Food and Drug Administration, and the National Institutes of Health. Emily T. Martin reports institutional grant support from Merck. Arnold S. Monto reports personal fees from Sanofi and non‐financial support from Seqirus. Mary Patricia Nowalk reports unrelated institutional grant support and personal fees from Merck Sharp & Dohme and institutional investigator‐initiated grant support from Sanofi Pasteur. Sara Y. Tartof reports unrelated institutional grant support from Pfizer and GlaxoSmithKline. No other potential conflicts of interest were disclosed., (Published 2022. This article is a U.S. Government work and is in the public domain in the USA. Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd.)

The SARS-CoV-2 Omicron variant (B.1.1.529 or BA.1) became predominant in the United States by late December 2021 (1). BA.1 has since been replaced by emerging lineages BA.2 (including BA.2.12.1) in March 2022, followed by BA.4 and BA.5, which have accounted for a majority of SARS-CoV-2 infections since late June 2022 (1). Data on the effectiveness of monovalent mRNA COVID-19 vaccines against BA.4/BA.5-associated hospitalizations are limited, and their interpretation is complicated by waning of vaccine-induced immunity (2-5). Further, infections with earlier Omicron lineages, including BA.1 and BA.2, reduce vaccine effectiveness (VE) estimates because certain persons in the referent unvaccinated group have protection from infection-induced immunity. The IVY Network † assessed effectiveness of 2, 3, and 4 doses of monovalent mRNA vaccines compared with no vaccination against COVID-19-associated hospitalization among immunocompetent adults aged ≥18 years during December 26, 2021-August 31, 2022. During the BA.1/BA.2 period, VE 14-150 days after a second dose was 63% and decreased to 34% after 150 days. Similarly, VE 7-120 days after a third dose was 79% and decreased to 41% after 120 days. VE 7-120 days after a fourth dose was 61%. During the BA.4/BA.5 period, similar trends were observed, although CIs for VE estimates between categories of time since the last dose overlapped. VE 14-150 days and >150 days after a second dose was 83% and 37%, respectively. VE 7-120 days and >120 days after a third dose was 60%and 29%, respectively. VE 7-120 days after the fourth dose was 61%. Protection against COVID-19-associated hospitalization waned even after a third dose. The newly authorized bivalent COVID-19 vaccines include mRNA from the ancestral SARS-CoV-2 strain and from shared mRNA components between BA.4 and BA.5 lineages and are expected to be more immunogenic against BA.4/BA.5 than monovalent mRNA COVID-19 vaccines (6-8). All eligible adults aged ≥18 years § should receive a booster dose, which currently consists of a bivalent mRNA vaccine, to maximize protection against BA.4/BA.5 and prevent COVID-19-associated hospitalization., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Samuel M. Brown reports personal fees from Hamilton Ventilators outside the submitted work. Jonathan D. Casey reports grants from the National Institutes of Health (NIH) and U.S. Department of Defense (DoD), outside the submitted work. Steven Y. Chang reports consulting for PureTech Health in 2020 and Kiniksa Pharmaceuticals and membership on the safety monitoring board (DSMB) for an investigator-initiated study at UCLA. James D. Chappell reports grants from NIH and DoD during the conduct of the study. David J. Douin reports grants received from NIH and National Institute of General Medical Sciences, outside the submitted work. Abhijit Duggal reports grants from NIH and participation on a steering committee for ALung technologies, outside the submitted work. Matthew C. Exline reports grants from the NIH and Regeneron, as well as support from Abbott Labs for sponsored talks, outside the submitted work. D. Clark Files reports personal consultant fees from Cytovale and membership on DSMB from Medpace, outside the submitted work. Anne P. Frosch reports grants from NIH, outside the submitted work. Manjusha Gaglani reports grants from Abt Associates, Westat, Janssen, and participation as co-chair on the Infection Diseases and Immunizations Committee for the Texas Pediatric Society, outside the submitted work. Kevin W. Gibbs reports grants from NIH and DoD, and DoD funds for Military Health System Research Symposium travel in 2022, outside the submitted work. Adit A. Ginde reports grants from NIH, DoD, AbbVie, and Faron Pharmaceuticals, outside the submitted work. Michelle N. Gong reports grants from NIH, speaking at medicine grand rounds at New York Medical College, travel support for the American Thoracic Society executive meeting, DSMB membership fees from Regeneron, and participation on the scientific advisory panel for Endpoint, outside the submitted work. Carlos G. Grijalva reports consultancy fees from Pfizer, Merck, and Sanofi-Pasteur; grants from Campbell Alliance/Syneos Health, NIH, the Food and Drug Administration, Agency for Healthcare Research and Quality, and Sanofi, outside the submitted work. David N. Hager grants from NIH, outside the submitted work. Natasha Halasa reports grants and nonfinancial support from Sanofi, and grants from Quidel outside the submitted work. Nicholas J. Johnson reports grants from the NIH, DoD, University of Washington, and Medic One Foundation, outside the submitted work. Akram Khan reports grants from United Therapeutics, Johnson & Johnson, Ely Lilly, 4D Medical, Dompe Pharmaceuticals, and GlaxoSmithKline, outside the submitted work. Jennie H. Kwon reports grants from National Institute of Allergy and Infectious Diseases (NIAID), outside the submitted work. Adam S. Lauring reports personal fees from Sanofi and Roche and grants from NIAID, Burroughs Wellcome Fund, Flu Lab, outside the submitted work. Emily T. Martin reports grants from Merck, outside the submitted work. Tresa McNeal reports participation as a webinar invited panelist and a Practice Management Committee member for Society of Hospital Medicine, outside the submitted work. Ithan D. Peltan reports grants from NIH, Janssen Pharmaceuticals and institutional support from Asahi Kasei Pharma and Regeneron, outside the submitted work. Todd W. Rice reports grants from Abbvie Inc, and personal fees from Cumberland Pharmaceuticals, Inc, Cytovale, Inc., and Sanofi, Inc., outside the submitted work. William B. Stubblefield reports grants from NIH, outside the submitted work. Jennifer G. Wilson reports grants from NIH, and personal funds from the American College of Emergency Physicians and American Board of Internal Medicine, outside the submitted work. No other potential conflicts of interest were disclosed.

Background . Adults in the United States (US) began receiving the adenovirus vector coronavirus disease 2019 (COVID-19) vaccine, Ad26.COV2.S (Johnson & Johnson [Janssen]), in February 2021. We evaluated Ad26.COV2.S vaccine effectiveness (VE) against COVID-19 hospitalization and high disease severity during the first 10 months of its use. Methods . In a multicenter case-control analysis of US adults (≥18 years) hospitalized 11 March to 15 December 2021, we estimated VE against susceptibility to COVID-19 hospitalization (VEs), comparing odds of prior vaccination with a single dose Ad26.COV2.S vaccine between hospitalized cases with COVID-19 and controls without COVID-19. Among hospitalized patients with COVID-19, we estimated VE against disease progression (VEp) to death or invasive mechanical ventilation (IMV), comparing odds of prior vaccination between patients with and without progression. Results . After excluding patients receiving mRNA vaccines, among 3979 COVID-19 case-patients (5% vaccinated with Ad26.COV2.S) and 2229 controls (13% vaccinated with Ad26.COV2.S), VEs of Ad26.COV2.S against COVID-19 hospitalization was 70% (95% confidence interval [CI]: 63-75%) overall, including 55% (29-72%) among immunocompromised patients, and 72% (64-77%) among immunocompetent patients, for whom VEs was similar at 14-90 days (73% [59-82%]), 91-180 days (71% [60-80%]), and 181-274 days (70% [54-81%]) postvaccination. Among hospitalized COVID-19 case-patients, VEp was 46% (18-65%) among immunocompetent patients. Conclusions . The Ad26.COV2.S COVID-19 vaccine reduced the risk of COVID-19 hospitalization by 72% among immunocompetent adults without waning through 6 months postvaccination. After hospitalization for COVID-19, vaccinated immunocompetent patients were less likely to require IMV or die compared to unvaccinated immunocompetent patients., Competing Interests: Potential conflicts of interest. M. G.: CDC: Baylor Scott & White Health (BSWH) US Flu/COVID VE Network, HAIVEN, Synergy studies; CDC-Abt: BSWH FluVax Trial and RECOVER-PROTECT Cohort Studies; CDC-Westat: BSWH VISION COVID-Flu VE Study; Janssen: BSWH Respiratory Syncytial Virus (RSV) Severity App Birth Cohort Study; Co-Chair of Infectious Diseases and Immunization Committee—Texas Pediatric Society—Texas Chapter of American Academy of Pediatrics. A. G.: National Institutes of Health (NIH), Department of Defense; Faron Pharmaceuticals; AbbVie; D Douin: NIH/National Institute of General Medical Sciences (NIGMS) Institutional Training Grant. J. C.: NIH and Department of Defense grants unrelated to this work. T. A. M.: Panelist for Society of Hospital Medicine Updates in Heart Failure; Board member for Scott & White Clinic Physicians Board of Directors. K. G.: NECTAR Executive Committee member ACTIV4-HT; D. C. F.: Cytovale consulting fees; Medpace Data Safety Monitoring Board. D. N. H.: National Heart, Lung, and Blood Institute (NIHLBI) participant in the ACTIV4d-Host Tissue Trial; Chair DSMD—SAFE EVICT Trial of VIT C in COVID-19. M. N. G.: Grants from NHLBI and Agency for Healthcare Research and Quality (AHRQ); Consulting fees for Endpoint for scientific advisory panel; Honoraria—Medicine Grand Rounds from Westchester Medical Center; Support for attending ATS Board of Directors meeting; Data and Safety Monitoring Board (DSMB) for Regeneron study and REPLENISH trial. N. J. J.: IH grants paid to University of Washington Royalty Research Fund; Department of Defense grants; Medic One Foundation grants; WA Department of Health expert testimony payment; DSMB for Opticyte, Inc.; Chair, ACEP Critical Care Section. I. P.: NIH grants; Regeneron Pharmaceuticals grant; Intermountain Research & Medical Foundation grant; Asahi Kasei Pharma grant; Janssen Pharmaceuticals grant. S. B.: NIH grants and Department of Defense grants; DSMB for Hamilton ventilators and NYU. E. T. M.: Merck grant. A. S. M.: NIH grant. A. K.: NIH grants; United Therapeutics grants; Eli Lily grants; Johnson & Johnson—BOA Medical—4DMedical research grants; rA. D.: Center PI for PETAL network through NHLBI grant; on steering committee for A Lung technologies. J. G. W.: NIH/NHLBI funding for ACTIV-3 and ACTIV-4 trials; American Board of Internal Medicine—member of Critical Care Exam Committee. S. Y. C.: Consulting fees for PureTech Health and Kiniska Pharmaceuticals; Honoraria for La Jolla. H. M. B.: CDC grant for HCP COVID vaccine effectiveness. J. H. K.: NIAID grant. M. C. E.: Abbott Labs honoraria for speaking on ASPEN on nutrition in critical illness from COVID. A. L.: grants from CDC, NIH, and Burroughs Wellcome Fund; consulting fees from Sanofi on antiviral drugs and for Roche on baloxavir trial steering committee. N. H.: grants from NIH, Quidel, and Sanofi; Honoraria for speaking at CME event at AAP. C. G. G.: grants from Campbell Alliance/Syneos Health, Sanofi, CDC, AHRQ, NIH, and FDA; consulting fees from Merck, Pfizer, and Sanofi-Pasteur. T. W. R.: grants from NIH, Department of Defense and AbbVie; consulting fees for Cumberland Pharmaceuticals, Inc. and Cytovale, Inc.; DSMB for Sanofi, Inc.; Immediate Past President—ASPEN; Stock in Cumberland Pharmaceuticals, Inc. for consulting work. W. B. S.: NIH training grants. C. J. L.: grants from NIH, Department of Defense; CDC; bioMerieux; Entegrion, Inc.; Endpoint Health; AbbVie; Patents for risk stratification in sepsis and septic shock issued to Cincinnati Children’s Hospital Medical Center; DSMBs for clinical trials for Study Principal Investigators; Association for Clinical and Translational Science (Executive Committee, Immediate Past President, and Board of Directors); stock options in Bioscape Digita. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2022.)

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses continue to co-circulate, representing 2 major public health threats from respiratory infections with similar clinical presentations. SARS-CoV-2 and influenza vaccines can also now be co-administered. However, data on antibody responses to SARS-CoV-2 and influenza coinfection and vaccine co-administration remain limited., Methods: We developed a 41-plex antibody immunity assay that can simultaneously characterize antibody landscapes to SARS-CoV-2/influenza/common human coronaviruses. We analyzed sera from 840 individuals (11-93 years), including sera from reverse transcription-polymerase chain reaction (RT-PCR)-confirmed SARS-CoV-2-positive (n = 218) and -negative (n = 120) cases, paired sera from SARS-CoV-2 vaccination (n = 29) and infection (n = 11), and paired sera from influenza vaccination (n = 56) and RT-PCR-confirmed influenza infection (n = 158) cases. Last, we analyzed sera collected from 377 individuals who exhibited acute respiratory illness (ARI) in 2020., Results: This 41-plex assay has high sensitivity and specificity in detecting SARS-CoV-2 infections. It differentiated SARS-CoV-2 vaccination (antibody responses only to spike protein) from infection (antibody responses to both spike and nucleoprotein). No cross-reactive antibodies were induced to SARS-CoV-2 from influenza vaccination and infection, and vice versa, suggesting no interaction between SARS-CoV-2 and influenza antibody responses. However, cross-reactive antibodies were detected between spike proteins of SARS-CoV-2 and common human coronaviruses that were removed by serum adsorption. Among 377 individuals who exhibited ARI in 2020, 129 were influenza positive; none had serological evidence of SARS-CoV-2/influenza coinfections., Conclusions: Multiplex detection of antibody landscapes can provide in-depth analysis of the antibody protective immunity to SARS-CoV-2 in the context of other respiratory viruses, including influenza., Competing Interests: Potential conflicts of interest. E. T. M. reports funding from the CDC and Merck. J. P. K. reports funding to their institution for research support from the CDC. K. W. reports funding to their institution from the CDC for the study (75D30121C11909). M. G. reports funding for the BSWH Ambulatory US Flu VE Network Study, BSWH HAIVEN and Synergy Studies, BSWH Flu VaxTrial and RECOVER-PROTECT Studies, and BSWH VISION COVID/FLU VE Study from the CDC. M.G. also report funding for the RSV Severity App Birth Cohort Study from Janssen, and being the co-chair of the Infectious Diseases and Immunization Committee of Texas Pediatric Society. R. K. Z. reports receiving grant funding from the CDC and grants for vaccine research from Sanofi Pasteur and the National Institutes of Health. M. D. L. J. reports receiving support for the HEROES project. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (Published by Oxford University Press on behalf of Infectious Diseases Society of America 2022.)

Background: The study objective was to evaluate 2- and 3-dose coronavirus disease 2019 (COVID-19) mRNA vaccine effectiveness (VE) in preventing COVID-19 hospitalization among adult solid organ transplant (SOT) recipients., Methods: We conducted a 21-site case-control analysis of 10 425 adults hospitalized in March to December 2021. Cases were hospitalized with COVID-19; controls were hospitalized for an alternative diagnosis (severe acute respiratory syndrome coronavirus 2-negative). Participants were classified as follows: SOT recipient (n = 440), other immunocompromising condition (n = 1684), or immunocompetent (n = 8301). The VE against COVID-19-associated hospitalization was calculated as 1-adjusted odds ratio of prior vaccination among cases compared with controls., Results: Among SOT recipients, VE was 29% (95% confidence interval [CI], -19% to 58%) for 2 doses and 77% (95% CI, 48% to 90%) for 3 doses. Among patients with other immunocompromising conditions, VE was 72% (95% CI, 64% to 79%) for 2 doses and 92% (95% CI, 85% to 95%) for 3 doses. Among immunocompetent patients, VE was 88% (95% CI, 87% to 90%) for 2 doses and 96% (95% CI, 83% to 99%) for 3 doses., Conclusions: Effectiveness of COVID-19 mRNA vaccines was lower for SOT recipients than immunocompetent adults and those with other immunocompromising conditions. Among SOT recipients, vaccination with 3 doses of an mRNA vaccine led to substantially greater protection than 2 doses., Competing Interests: Potential conflicts of interest. All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. J. H. K. reports grant support from National Institutes of Health (NIH)/National Institute of Allergy and Infectious Diseases (1K23 AI137321-01A1). M. G. reports grant support from CDC, CDC-Abt, CDC-Westat, and Janssen and a role as the Co-Chair of the Infectious Diseases and Immunization Committee, Texas Pediatric Society, Texas Chapter of American Academy of Pediatrics (AAP). H. K. T. reports a grant from CDC. A. A. G. reports grant support from CDC, NIH, US Department of Defense (DOD), AbbVie, and Faron Pharmaceuticals. T. M. reports payments as a panelist for the Society of Hospital Medicine Updates in Heart Failure (August 25, 2021) and as a board member of the Scott & White Clinic Physicians Board of Directors. D. J. D. reports grant support from NIH/National Institute of General Medical Sciences (T32GM135169). J. D. C. reports grants from the NIH and DOD. K. W. G. reports grant support as a NECTAR Executive Committee member ACTIV-4HT. D. C. F. reports consultant fees from Cytovale and membership on a Medpace Data Safety Monitoring Board (DSMB). D. N. H. reports a contract from CDC and grant support from National Heart, Lung, and Blood Institute (NHLBI) for participation in the ACTIV4d-Host Tissue Trial. M. C. E. reports talks on nutrition in COVID pneumonia at ASPEN conference sponsored by Abbott Laboratories. M. N. G. reports grant support from the CDC, funding from NHLBI and Agency for Healthcare Research and Quality (AHRQ), and fees from Endpoint for participating on a scientific advisory panel, payment for Medicine Grand Rounds at Westchester Medical Center, travel support for attending the ATS Board of Directors meeting, and participation on a DSMB for Regeneron and REPLINISH trial. N. J. J. reports grants from the NIH, DOD, and Medic One Foundation, payment for expert testimony from the Washington Department of Health, participation on DSMBs for Opticyte Inc., Multi-Center, Randomized Control Trial to Study the Effectiveness of Hyperbaric Oxygen for COVID-19 patients with Moderate to Severe Hypoxemia (NCT04619719), and Remote Ischemic Conditioning to Enhance Resuscitation (RICE) Pilot (NCT04265807), and participation as Chair of the ACEP Critical Care Section. I. D. P. reports grants from the CDC, NIH, Janssen Pharmaceuticals, and Intermountain Research & Medical Foundation, institutional fees from Asahi Kasei Pharma and from Regeneron Pharmaceuticals. S. M. B. reports grants from the CDC, NIH, and DOD, fees from Hamilton ventilators for chairing a DSMB, and personal fees from New York University for service on a DSMB. E. T. M. reports a grant from Merck outside the submitted work. A. K. reports grants from the NIH, Ely Lily, United Therapeutics, Johnson & Johnson, BOA Medical, and 4D Medical. A. D. reports funding as the Center PI for PETAL network through NHLBI grant and for participation on a steering committee for ALung technologies. J. G. W. reports grant support from NIH/NHLBI for ACTIV-3 and ACTIV-4 trials and membership on the American Board of Internal Medicine Critical Care Exam Committee. S. Y. C. reports payment as a speaker for La Jolla Pharmaceuticals and consultant fees for PureTech Health and Kiniska Pharmaceuticals. H. M. B. reports grants from the CDC. A. S. L. reports grants from the CDC, NIH, and Burroughs Wellcome Fund, consultant fees from Sanofi, and fees from Roche for membership on a trial steering committee. N. H. reports grants from the CDC, NIH, Sanofi, and Quidel and honoraria for speaking at Continuing Medical Education event at AAP. J. D. C. reports grant support from the CDC. C. G. G. reports consultant fees from Pfizer, Merck, and Sanofi-Pasteur and grants from Campbell Alliance/Syneos Health, CDC, NIH, US Food and Drug Administration, AHRQ, and Sanofi. T. W. R. reports grants from the NIH, DOD, and AbbVie, personal fees from Cumberland Pharmaceuticals as the Director of Medical Affairs, consultant fees from Cytovale, Inc., personal fees from Sanofi, Inc. for serving as a DSMB board member, a role as the Immediate Past President of the American Society of Parenteral and Enteral Nutrition (ASPEN), and stock from Cumberland Pharmaceuticals for consulting work. C J. L. reports grants/contracts from the CDC, NIH, DOD, bioMerieux, Endpoint LLC, Entegrion, Inc., and AbbVie, a patent issued to Cincinnati Children’s Hospital Medical Center for risk stratification in sepsis and septic shock, participation on DSMBS for Study Principal Investigators, roles on the Executive Committee, Immediate Past President, Member, Board of Directors for the Association of Clinical and Translational Science, and stock options in Bioscape Digita. W. H. S. reports grant funding from the CDC for this work. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background: Individuals in contact with persons with COVID-19 are at high risk of developing COVID-19; protection offered by COVID-19 vaccines in the context of known exposure is poorly understood., Methods: Symptomatic outpatients aged ≥12 years reporting acute onset of COVID-19-like illness and tested for SARS-CoV-2 between February 1 and September 30, 2021 were enrolled. Participants were stratified by self-report of having known contact with a COVID-19 case in the 14 days prior to illness onset. Vaccine effectiveness was evaluated using the test-negative study design and multivariable logistic regression., Results: Among 2229 participants, 283/451 (63%) of those reporting contact and 331/1778 (19%) without known contact tested SARS-CoV-2-positive. Adjusted vaccine effectiveness was 71% (95% confidence interval [CI], 49%-83%) among fully vaccinated participants reporting a known contact versus 80% (95% CI, 72%-86%) among those with no known contact (p-value for interaction = 0.2)., Conclusions: This study contributes to growing evidence of the benefits of vaccinations in preventing COVID-19 and support vaccination recommendations and the importance of efforts to increase vaccination coverage., (© Published 2022. This article is a U.S. Government work and is in the public domain in the USA. Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd.)

Vaccine effectiveness (VE) against COVID-19 hospitalization was evaluated among immunocompetent adults (≥18 years) during March-August 2021 using a case-control design. Among 1669 hospitalized COVID-19 cases (11% fully vaccinated) and 1950 RT-PCR-negative controls (54% fully vaccinated), VE was 96% (95% confidence interval [CI], 93%-98%) among patients with no chronic medical conditions and 83% (95% CI, 76%-88%) among patients with ≥ 3 categories of conditions. VE was similar between those aged 18-64 years versus ≥65 years (P > .05). VE against severe COVID-19 was very high among adults without chronic conditions and lessened with increasing comorbidity burden., (Published by Oxford University Press for the Infectious Diseases Society of America 2021.)

Background: As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination coverage increases in the United States, there is a need to understand the real-world effectiveness against severe coronavirus disease 2019 (COVID-19) and among people at increased risk for poor outcomes., Methods: In a multicenter case-control analysis of US adults hospitalized March 11-May 5, 2021, we evaluated vaccine effectiveness to prevent COVID-19 hospitalizations by comparing odds of prior vaccination with a messenger RNA (mRNA) vaccine (Pfizer-BioNTech or Moderna) between cases hospitalized with COVID-19 and hospital-based controls who tested negative for SARS-CoV-2., Results: Among 1212 participants, including 593 cases and 619 controls, median age was 58 years, 22.8% were Black, 13.9% were Hispanic, and 21.0% had immunosuppression. SARS-CoV-2 lineage B0.1.1.7 (Alpha) was the most common variant (67.9% of viruses with lineage determined). Full vaccination (receipt of 2 vaccine doses ≥14 days before illness onset) had been received by 8.2% of cases and 36.4% of controls. Overall vaccine effectiveness was 87.1% (95% confidence interval [CI], 80.7-91.3). Vaccine effectiveness was similar for Pfizer-BioNTech and Moderna vaccines, and highest in adults aged 18-49 years (97.4%; 95% CI, 79.3-9.7). Among 45 patients with vaccine-breakthrough COVID hospitalizations, 44 (97.8%) were ≥50 years old and 20 (44.4%) had immunosuppression. Vaccine effectiveness was lower among patients with immunosuppression (62.9%; 95% CI,20.8-82.6) than without immunosuppression (91.3%; 95% CI, 85.6-94.8)., Conclusion: During March-May 2021, SARS-CoV-2 mRNA vaccines were highly effective for preventing COVID-19 hospitalizations among US adults. SARS-CoV-2 vaccination was beneficial for patients with immunosuppression, but effectiveness was lower in the immunosuppressed population., (© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Short-term probabilistic forecasts of the trajectory of the COVID-19 pandemic in the United States have served as a visible and important communication channel between the scientific modeling community and both the general public and decision-makers. Forecasting models provide specific, quantitative, and evaluable predictions that inform short-term decisions such as healthcare staffing needs, school closures, and allocation of medical supplies. Starting in April 2020, the US COVID-19 Forecast Hub (https://covid19forecasthub.org/) collected, disseminated, and synthesized tens of millions of specific predictions from more than 90 different academic, industry, and independent research groups. A multimodel ensemble forecast that combined predictions from dozens of groups every week provided the most consistently accurate probabilistic forecasts of incident deaths due to COVID-19 at the state and national level from April 2020 through October 2021. The performance of 27 individual models that submitted complete forecasts of COVID-19 deaths consistently throughout this year showed high variability in forecast skill across time, geospatial units, and forecast horizons. Two-thirds of the models evaluated showed better accuracy than a naïve baseline model. Forecast accuracy degraded as models made predictions further into the future, with probabilistic error at a 20-wk horizon three to five times larger than when predicting at a 1-wk horizon. This project underscores the role that collaboration and active coordination between governmental public-health agencies, academic modeling teams, and industry partners can play in developing modern modeling capabilities to support local, state, and federal response to outbreaks.

COVID-19 mRNA vaccines (BNT162b2 [Pfizer-BioNTech] and mRNA-1273 [Moderna]) are effective at preventing COVID-19-associated hospitalization (1-3). However, how well mRNA vaccines protect against the most severe outcomes of these hospitalizations, including invasive mechanical ventilation (IMV) or death is uncertain. Using a case-control design, mRNA vaccine effectiveness (VE) against COVID-19-associated IMV and in-hospital death was evaluated among adults aged ≥18 years hospitalized at 21 U.S. medical centers during March 11, 2021-January 24, 2022. During this period, the most commonly circulating variants of SARS-CoV-2, the virus that causes COVID-19, were B.1.1.7 (Alpha), B.1.617.2 (Delta), and B.1.1.529 (Omicron). Previous vaccination (2 or 3 versus 0 vaccine doses before illness onset) in prospectively enrolled COVID-19 case-patients who received IMV or died within 28 days of hospitalization was compared with that among hospitalized control patients without COVID-19. Among 1,440 COVID-19 case-patients who received IMV or died, 307 (21%) had received 2 or 3 vaccine doses before illness onset. Among 6,104 control-patients, 4,020 (66%) had received 2 or 3 vaccine doses. Among the 1,440 case-patients who received IMV or died, those who were vaccinated were older (median age = 69 years), more likely to be immunocompromised* (40%), and had more chronic medical conditions compared with unvaccinated case-patients (median age = 55 years; immunocompromised = 10%; p<0.001 for both). VE against IMV or in-hospital death was 90% (95% CI = 88%-91%) overall, including 88% (95% CI = 86%-90%) for 2 doses and 94% (95% CI = 91%-96%) for 3 doses, and 94% (95% CI = 88%-97%) for 3 doses during the Omicron-predominant period. COVID-19 mRNA vaccines are highly effective in preventing COVID-19-associated death and respiratory failure treated with IMV. CDC recommends that all persons eligible for vaccination get vaccinated and stay up to date with COVID-19 vaccination (4)., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Samuel M. Brown reports personal fees from Hamilton ventilators, and grants from the National Institutes of Health (NIH) and the U.S. Department of Defense (DoD). Jonathan D. Casey reports grants from the NIH and DoD. Steven Y. Chang was a speaker for La Jolla Pharmaceuticals in 2018, consulted for PureTech Health in 2020, and consulted for Kiniska Pharmaceuticals in December 2021. David J. Douin reports a grant from NIH/National Institute of General Medical Sciences. Abhijit Duggal reports grants from NIH and participation on a Steering Committee for ALung Technologies. Matthew C. Exline reports support from Abbott Labs for sponsored talks. D. Clark Files reports personal consultant fees from Cytovale and membership on a data and safety monitoring board (DSMB) from Medpace. Anne E. Frosch reports grants from NIH/National Institute of Allergy and Infectious Diseases (NIAID), NIH/National Heart, Lung, and Blood Institute (NHLBI), and NIH/INSIGHT/ICC. Manjusha Gaglani reports grants from Abt Associates, Westat, and Janssen. Adit A. Ginde reports grants from NIH, DoD, AbbVie, and Faron Pharmaceuticals. Michelle N. Gong reports grants from NIH and the Agency for Healthcare Research and Quality (AHRQ), and DSMB membership fees from Regeneron, outside the submitted work. Carlos G. Grijalva reports consultancy fees from Pfizer, Merck, and Sanofi-Pasteur; grants from Campbell Alliance/Syneos Health, NIH, the Food and Drug Administration, AHRQ, and Sanofi. David N. Hager reports grants from NIH/NHLBI. Natasha Halasa reports grants and nonfinancial support from Sanofi, and grants from Quidel and NIH. Nicholas J. Johnson reports grants from NIH, DoD, and Medic One Foundation. Akram Khan reports grants from United Therapeutics, Johnson & Johnson, and Eli Lilly. Jennie H. Kwon reports grants from NIH/NIAID. Adam S. Lauring reports personal fees from Sanofi and Roche, and grants from NIH and Burroughs Wellcome Fund. Christopher J. Lindsell reports grants from NIH, DoD, and the Marcus Foundation; contract fees from bioMerieux, Endpoint Health, Entegrion Inc, and AbbVie; and a patent for risk stratification in sepsis and septic shock. Emily T. Martin reports grants from Merck. Arnold S. Monto reports a grant from NIH. Ithan D. Peltan reports grants from NIH, Janssen Pharmaceuticals, and Intermountain Research and Medical Foundation, and institutional support from Asahi Kasei Pharma and Regeneron. Todd W. Rice reports grants from NIH, DoD, and AbbVie and personal fees from Cumberland Pharmaceuticals, Inc., and Cytovale, Inc. No other potential conflicts of interest were disclosed.

COVID-19 mRNA vaccines (BNT162b2 [Pfizer-BioNTech] and mRNA-1273 [Moderna]) provide protection against infection with SARS-CoV-2, the virus that causes COVID-19, and are highly effective against COVID-19-associated hospitalization among eligible persons who receive 2 doses (1,2). However, vaccine effectiveness (VE) among persons with immunocompromising conditions* is lower than that among immunocompetent persons (2), and VE declines after several months among all persons (3). On August 12, 2021, the Food and Drug Administration (FDA) issued an emergency use authorization (EUA) for a third mRNA vaccine dose as part of a primary series ≥28 days after dose 2 for persons aged ≥12 years with immunocompromising conditions, and, on November 19, 2021, as a booster dose for all adults aged ≥18 years at least 6 months after dose 2, changed to ≥5 months after dose 2 on January 3, 2022 (4,5,6). Among 2,952 adults (including 1,385 COVID-19 case-patients and 1,567 COVID-19-negative controls) hospitalized at 21 U.S. hospitals during August 19-December 15, 2021, effectiveness of mRNA vaccines against COVID-19-associated hospitalization was compared between adults eligible for but who had not received a third vaccine dose (1,251) and vaccine-eligible adults who received a third dose ≥7 days before illness onset (312). Among 1,875 adults without immunocompromising conditions (including 1,065 [57%] unvaccinated, 679 [36%] 2-dose recipients, and 131 [7%] 3-dose [booster] recipients), VE against COVID-19 hospitalization was higher among those who received a booster dose (97%; 95% CI = 95%-99%) compared with that among 2-dose recipients (82%; 95% CI = 77%-86%) (p <0.001). Among 1,077 adults with immunocompromising conditions (including 324 [30%] unvaccinated, 572 [53%] 2-dose recipients, and 181 [17%] 3-dose recipients), VE was higher among those who received a third dose to complete a primary series (88%; 95% CI = 81%-93%) compared with 2-dose recipients (69%; 95% CI = 57%-78%) (p <0.001). Administration of a third COVID-19 mRNA vaccine dose as part of a primary series among immunocompromised adults, or as a booster dose among immunocompetent adults, provides improved protection against COVID-19-associated hospitalization., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Samuel M. Brown reports personal fees from Hamilton, institutional fees from Faron Pharmaceuticals and Sedana, grants from Janssen, the National Institutes of Health (NIH), the Department of Defense (DoD), book royalties from Oxford University and Brigham Young University, outside the submitted work. Steven Y. Chang was a speaker for La Jolla Pharmaceuticals in 2018 and consulted for PureTech Health in 2020. James D. Chappell reports grants from NIH during the conduct of the study. Abhijit Duggal reports grants from NIH and participation on a steering committee for ALung Technologies, Inc., outside the submitted work. Matthew C. Exline reports support from Abbott Labs for sponsored talks, outside the submitted work. D. Clark Files reports personal consultant fees from Cytovale and is a data and safety monitoring board (DSMB) member from Medpace, outside the submitted work. Manjusha Gaglani reports grants from CDC-Vanderbilt University Medical Center for the submitted work, CDC-Abt Associates, CDC-Westat, Janssen and Pfizer, outside the submitted work. Adit A. Ginde reports grants from NIH, DoD, AbbVie, and Faron Pharmaceuticals, outside the submitted work. Michelle N. Gong reports grants from NIH and the Agency for Healthcare Research and Quality (AHRQ), DSMB membership fees from Regeneron, outside the submitted work. Carlos G. Grijalva reports consultancy fees from Pfizer, Merck, and Sanofi-Pasteur; grants from Campbell Alliance/Syneos Health, NIH, the Food and Drug Administration, AHRQ, and Sanofi, outside the submitted work. David N. Hager reports salary support from Incyte Corporation and EMPACT Precision Medicine via Vanderbilt University Medical Center and grants from NHLBI, outside the submitted work. Natasha Halasa reports grants and nonfinancial support from Sanofi, and grants from Quidel outside the submitted work. Akram Khan reports grants from United Therapeutics, Johnson & Johnson, Ely Lilly, and GlaxoSmithKline, outside the submitted work. Adam S. Lauring reports personal fees from Sanofi and Roche, outside the submitted work. Christopher J. Lindsell reports grants from NIH, DoD, and the Marcus Foundation; contract fees from bioMerieux, Endpoint LLC, and Entegrion Inc, outside the submitted work; in addition, Dr. Lindsell has a patent for risk stratification in sepsis and septic shock issued. Emily T. Martin reports personal fees from Pfizer and grants from Merck, outside the submitted work. Ithan D. Peltan reports grants from NIH, Janssen Pharmaceuticals and institutional support from Asahi Kasei Pharma and Regeneron, outside the submitted work. Todd W. Rice reports personal fees from Cumberland Pharmaceuticals, Inc, Cytovale, Inc., and Sanofi, Inc., outside the submitted work. Wesley H. Self reports consulting fees from Aeprio Pharmaceuticals and Merck, outside the submitted work. No other potential conflicts of interest were disclosed.

Background: SARS-CoV-2 outbreaks in nursing homes (NHs) have been devastating and have led to the creation of coronavirus disease 2019 (COVID-19) units within NHs to care for affected patients. Frequency and persistence of SARS-CoV-2 environmental contamination in these units have not been studied., Methods: A prospective cohort study was conducted between October 2020 and January 2021 in four Michigan NHs. Swabs from high-touch surfaces in COVID-19-infected patient rooms were obtained at enrollment and follow-up. Demographic and clinical data were collected from clinical records. Primary outcome of interest was the probability of SARS-CoV-2 RNA detection from specific environmental surfaces in COVID-19 patient rooms. We used multivariable logistic regression to assess patient risk factors for SARS-CoV-2 contamination. Pairwise Phi coefficients were calculated to measure correlation of site-specific environmental detection upon enrollment and during follow-up., Results: One hundred and four patients with COVID-19 were enrolled (61.5% >80 years; 67.3% female; 89.4% non-Hispanic White; 51% short stay) and followed up for 241 visits. The study population had significant disabilities in activities of daily living (ADL; 81.7% dependent in four or more ADLs) and comorbidities, including dementia (55.8%), diabetes (40.4%), and heart failure (32.7%). Over the 3-month study period, 2087 swab specimens were collected (1896 COVID-19 patient rooms, 191 common areas). SARS-CoV-2 positivity was 28.4% (538/1896 swabs) on patient room surfaces and 3.7% (7/191 swabs) on common area surfaces. Nearly 90% (93/104) of patients had SARS-CoV-2 contamination in their room at least once. Environmental contamination upon enrollment correlated with contamination of the same site during follow-up. Functional independence increased the odds of proximate contamination., Conclusions: Environmental detection of viral RNA from surfaces in the rooms of COVID-19 patients is nearly universal and persistent; more investigation is needed to determine the implications of this for infectiousness. Patients with greater independence are more likely than fully dependent patients to contaminate their immediate environment., (© 2021 The American Geriatrics Society. This article has been contributed to by US Government employees and their work is in the public domain in the USA.)

Background: Novel coronavirus disease 2019 (COVID-19) is frequently compared with influenza. The Hospitalized Adult Influenza Vaccine Effectiveness Network (HAIVEN) conducts studies on the etiology and characteristics of U.S. hospitalized adults with influenza. It began enrolling patients with COVID-19 hospitalizations in March 2020. Patients with influenza were compared with those with COVID-19 in the first months of the U.S. epidemic., Methods: Adults aged ≥ 18 years admitted to hospitals in 4 sites with acute respiratory illness were tested by real-time reverse transcription polymerase chain reaction for influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing COVID-19. Demographic and illness characteristics were collected for influenza illnesses during 3 seasons 2016-2019. Similar data were collected on COVID-19 cases admitted before June 19, 2020., Results: Age groups hospitalized with COVID-19 (n = 914) were similar to those admitted with influenza (n = 1937); 80% of patients with influenza and 75% of patients with COVID-19 were aged ≥50 years. Deaths from COVID-19 that occurred in younger patients were less often related to underlying conditions. White non-Hispanic persons were overrepresented in influenza (64%) compared with COVID-19 hospitalizations (37%). Greater severity and complications occurred with COVID-19 including more ICU admissions (AOR = 15.3 [95% CI: 11.6, 20.3]), ventilator use (AOR = 15.6 [95% CI: 10.7, 22.8]), 7 additional days of hospital stay in those discharged alive, and death during hospitalization (AOR = 19.8 [95% CI: 12.0, 32.7])., Conclusions: While COVID-19 can cause a respiratory illness like influenza, it is associated with significantly greater severity of illness, longer hospital stays, and higher in-hospital deaths., (© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Importance: A comprehensive understanding of the benefits of COVID-19 vaccination requires consideration of disease attenuation, determined as whether people who develop COVID-19 despite vaccination have lower disease severity than unvaccinated people., Objective: To evaluate the association between vaccination with mRNA COVID-19 vaccines-mRNA-1273 (Moderna) and BNT162b2 (Pfizer-BioNTech)-and COVID-19 hospitalization, and, among patients hospitalized with COVID-19, the association with progression to critical disease., Design, Setting, and Participants: A US 21-site case-control analysis of 4513 adults hospitalized between March 11 and August 15, 2021, with 28-day outcome data on death and mechanical ventilation available for patients enrolled through July 14, 2021. Date of final follow-up was August 8, 2021., Exposures: COVID-19 vaccination., Main Outcomes and Measures: Associations were evaluated between prior vaccination and (1) hospitalization for COVID-19, in which case patients were those hospitalized for COVID-19 and control patients were those hospitalized for an alternative diagnosis; and (2) disease progression among patients hospitalized for COVID-19, in which cases and controls were COVID-19 patients with and without progression to death or mechanical ventilation, respectively. Associations were measured with multivariable logistic regression., Results: Among 4513 patients (median age, 59 years [IQR, 45-69]; 2202 [48.8%] women; 23.0% non-Hispanic Black individuals, 15.9% Hispanic individuals, and 20.1% with an immunocompromising condition), 1983 were case patients with COVID-19 and 2530 were controls without COVID-19. Unvaccinated patients accounted for 84.2% (1669/1983) of COVID-19 hospitalizations. Hospitalization for COVID-19 was significantly associated with decreased likelihood of vaccination (cases, 15.8%; controls, 54.8%; adjusted OR, 0.15; 95% CI, 0.13-0.18), including for sequenced SARS-CoV-2 Alpha (8.7% vs 51.7%; aOR, 0.10; 95% CI, 0.06-0.16) and Delta variants (21.9% vs 61.8%; aOR, 0.14; 95% CI, 0.10-0.21). This association was stronger for immunocompetent patients (11.2% vs 53.5%; aOR, 0.10; 95% CI, 0.09-0.13) than immunocompromised patients (40.1% vs 58.8%; aOR, 0.49; 95% CI, 0.35-0.69) (P < .001) and weaker at more than 120 days since vaccination with BNT162b2 (5.8% vs 11.5%; aOR, 0.36; 95% CI, 0.27-0.49) than with mRNA-1273 (1.9% vs 8.3%; aOR, 0.15; 95% CI, 0.09-0.23) (P < .001). Among 1197 patients hospitalized with COVID-19, death or invasive mechanical ventilation by day 28 was associated with decreased likelihood of vaccination (12.0% vs 24.7%; aOR, 0.33; 95% CI, 0.19-0.58)., Conclusions and Relevance: Vaccination with an mRNA COVID-19 vaccine was significantly less likely among patients with COVID-19 hospitalization and disease progression to death or mechanical ventilation. These findings are consistent with risk reduction among vaccine breakthrough infections compared with absence of vaccination.

Evaluations of vaccine effectiveness (VE) are important to monitor as coronavirus disease 2019 (COVID-19) vaccines are introduced in the general population. Research staff enrolled symptomatic participants seeking outpatient medical care for COVID-19-like illness or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing from a multisite network. VE was evaluated using the test-negative design. Among 236 SARS-CoV-2 nucleic acid amplification test-positive and 576 test-negative participants aged ≥16 years, the VE of messenger RNA vaccines against COVID-19 was 91% (95% confidence interval, 83%-95%) for full vaccination and 75% (55%-87%) for partial vaccination. Vaccination was associated with prevention of most COVID-19 cases among people seeking outpatient medical care., (Published by Oxford University Press for the Infectious Diseases Society of America 2021.)

Background: Previous studies demonstrated that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA can be detected for weeks after infection. The significance of this finding is unclear and, in most patients, does not represent active infection. Detection of subgenomic RNA has been proposed to represent productive infection and may be a useful marker for monitoring infectivity., Methods: We used quantitative reverse-transcription polymerase chain reaction (RT-qPCR) to quantify total and subgenomic nucleocapsid (sgN) and envelope (sgE) transcripts in 185 SARS-CoV-2-positive nasopharyngeal swab samples collected on hospital admission and to relate to symptom duration., Results: We find that all transcripts decline at the same rate; however, sgE becomes undetectable before other transcripts. The median duration of symptoms to a negative test is 14 days for sgE and 25 days for sgN. There is a linear decline in subgenomic compared to total RNA, suggesting that subgenomic transcript copy number is dependent on copy number of total transcripts. The mean difference between total and sgN is 16-fold and the mean difference between total and sgE is 137-fold. This relationship is constant over duration of symptoms, allowing prediction of subgenomic copy number from total copy number., Conclusions: Subgenomic RNA may be no more useful in determining infectivity than a copy number threshold determined for total RNA., (© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Three COVID-19 vaccines are authorized or approved for use among adults in the United States (1,2). Two 2-dose mRNA vaccines, mRNA-1273 from Moderna and BNT162b2 from Pfizer-BioNTech, received Emergency Use Authorization (EUA) by the Food and Drug Administration (FDA) in December 2020 for persons aged ≥18 years and aged ≥16 years, respectively. A 1-dose viral vector vaccine (Ad26.COV2 from Janssen [Johnson & Johnson]) received EUA in February 2021 for persons aged ≥18 years (3). The Pfizer-BioNTech vaccine received FDA approval for persons aged ≥16 years on August 23, 2021 (4). Current guidelines from FDA and CDC recommend vaccination of eligible persons with one of these three products, without preference for any specific vaccine (4,5). To assess vaccine effectiveness (VE) of these three products in preventing COVID-19 hospitalization, CDC and collaborators conducted a case-control analysis among 3,689 adults aged ≥18 years who were hospitalized at 21 U.S. hospitals across 18 states during March 11-August 15, 2021. An additional analysis compared serum antibody levels (anti-spike immunoglobulin G [IgG] and anti-receptor binding domain [RBD] IgG) to SARS-CoV-2, the virus that causes COVID-19, among 100 healthy volunteers enrolled at three hospitals 2-6 weeks after full vaccination with the Moderna, Pfizer-BioNTech, or Janssen COVID-19 vaccine. Patients with immunocompromising conditions were excluded. VE against COVID-19 hospitalizations was higher for the Moderna vaccine (93%; 95% confidence interval [CI] = 91%-95%) than for the Pfizer-BioNTech vaccine (88%; 95% CI = 85%-91%) (p = 0.011); VE for both mRNA vaccines was higher than that for the Janssen vaccine (71%; 95% CI = 56%-81%) (all p<0.001). Protection for the Pfizer-BioNTech vaccine declined 4 months after vaccination. Postvaccination anti-spike IgG and anti-RBD IgG levels were significantly lower in persons vaccinated with the Janssen vaccine than the Moderna or Pfizer-BioNTech vaccines. Although these real-world data suggest some variation in levels of protection by vaccine, all FDA-approved or authorized COVID-19 vaccines provide substantial protection against COVID-19 hospitalization., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Wesley H. Self reports grants and consultant fees from Merck and consultant fees from Aerpio Pharmaceuticals. Adit A. Ginde reports grant support from AbbVie and Faron Pharmaceuticals. Jonathan D. Casey reports a grant (N23HL153584) from the National Institutes of Health (NIH). D. Clark Files reports consultant fees from Cytovale and membership on a Medpace Data Safety Monitoring Board (DSMB). David N. Hager reports salary support from Incyte Corporation, EMPACT Precision Medicine, and the Marcus Foundation. Michelle N. Gong reports grant support from NIH and the Agency for Healthcare Research and Quality (AHRQ) and fees for participating on a DSMB for Regeneron and for participating on a scientific advisory panel for Philips Healthcare. Daniel J. Henning reports consulting fees from Cytovale and Opticyte. Ithan D. Peltan reports grants from NIH and Janssen Pharmaceuticals, institutional fees from Asahi Kasei Pharma and from Regeneron. Samuel M. Brown reports fees from Hamilton for chairing a DSMB, and institutional fees from Faron, Sedana, and Janssen; grants from Sedana, Janssen, NIH, and the Department of Defense (DoD); book royalties from Oxford University and Brigham Young University; and personal fees from New York University for service on a DSMB. Emily T. Martin reports personal fees from Pfizer for unrelated work and a grant from Merck for unrelated work. Akram Khan reports grants from United Therapeutics, Johnson & Johnson, 4D Medical, Lung LLC, and Reata Pharmaceuticals. Arnold S. Monto reports consulting fees from Sanofi-Pasteur and Seqirus. Steven Y. Chang was a speaker for La Jolla Pharmaceuticals and a Consultant for PureTech Health. Jennie H. Kwon reports grant support from NIH. Matthew C. Exline reports talks on nutrition in COVID pneumonia at APEN conference sponsored by Abbott Labs. Natasha Halasa reports grants from Sanofi and Quidel. James D. Chappell reports a grant from the National Center for Advancing Translational Sciences, NIH. Adam S. Lauring reports consultant fees from Sanofi and fees from Roche for membership on a trial steering committee. Carlos G. Grijalva reports consultant fees from Pfizer, Merck, and Sanofi-Pasteur and grants from Campbell Alliance/Syneos Health, NIH, the Food and Drug Administration, AHRQ, and Sanofi. Todd W. Rice reports personal fees from Cumberland Pharmaceuticals, Inc., as the Director of Medical Affairs, consultant fees from Avisa Pharma, LLC; and DSMB membership fees from Sanofi. Christopher J. Lindsell reports grants from NIH, DoD, and the Marcus Foundation; organizational contract fees from bioMerieux, Endpoint LLC, and Entegrion, Inc.; and a patent issued to Cincinnati Children’s Hospital Medical Center for risk stratification in sepsis and septic shock. No other potential conflicts of interest were disclosed.

Real-world evaluations have demonstrated high effectiveness of vaccines against COVID-19-associated hospitalizations (1-4) measured shortly after vaccination; longer follow-up is needed to assess durability of protection. In an evaluation at 21 hospitals in 18 states, the duration of mRNA vaccine (Pfizer-BioNTech or Moderna) effectiveness (VE) against COVID-19-associated hospitalizations was assessed among adults aged ≥18 years. Among 3,089 hospitalized adults (including 1,194 COVID-19 case-patients and 1,895 non-COVID-19 control-patients), the median age was 59 years, 48.7% were female, and 21.1% had an immunocompromising condition. Overall, 141 (11.8%) case-patients and 988 (52.1%) controls were fully vaccinated (defined as receipt of the second dose of Pfizer-BioNTech or Moderna mRNA COVID-19 vaccines ≥14 days before illness onset), with a median interval of 65 days (range = 14-166 days) after receipt of second dose. VE against COVID-19-associated hospitalization during the full surveillance period was 86% (95% confidence interval [CI] = 82%-88%) overall and 90% (95% CI = 87%-92%) among adults without immunocompromising conditions. VE against COVID-19- associated hospitalization was 86% (95% CI = 82%-90%) 2-12 weeks and 84% (95% CI = 77%-90%) 13-24 weeks from receipt of the second vaccine dose, with no significant change between these periods (p = 0.854). Whole genome sequencing of 454 case-patient specimens found that 242 (53.3%) belonged to the B.1.1.7 (Alpha) lineage and 74 (16.3%) to the B.1.617.2 (Delta) lineage. Effectiveness of mRNA vaccines against COVID-19-associated hospitalization was sustained over a 24-week period, including among groups at higher risk for severe COVID-19; ongoing monitoring is needed as new SARS-CoV-2 variants emerge. To reduce their risk for hospitalization, all eligible persons should be offered COVID-19 vaccination., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Samuel M. Brown reports personal fees from Hamilton, institutional fees from Faron Pharmaceuticals and Sedana, grants from Janssen, the National Institutes of Health (NIH), and the Department of Defense (DoD), book royalties from Oxford University and Brigham Young University, outside the submitted work. Jonathan D. Casey reports grants from NIH, outside the submitted work. Steven Y. Chang was a speaker for La Jolla Pharmaceuticals in 2018 and consulted for PureTech Health in 2020. James D. Chappell reports grants from NIH during the conduct of the study. Matthew C. Exline reports support from Abbott Labs for sponsored talks, outside the submitted work. D. Clark Files reports personal consultant fees from Cytovale and is a data and safety monitoring board (DSMB) member from Medpace, outside the submitted work. Adit A. Ginde reports grants from NIH, DoD, AbbVie, and Faron Pharmaceuticals, outside the submitted work. Michelle N. Gong reports grants from NIH and the Agency for Healthcare Research and Quality (AHRQ), DSMB membership fees from Regeneron, and personal fees from Philips Healthcare, outside the submitted work. Carlos G. Grijalva reports consultancy fees from Pfizer, Merck, and Sanofi-Pasteur; grants from Campbell Alliance/Syneos Health, NIH, the Food and Drug Administration, AHQR, and Sanofi, outside the submitted work. David N. Hager reports salary support from Incyte Corporation, the Marcus Foundation, and EMPACT Precision Medicine via Vanderbilt University Medical Center, outside the submitted work. Natasha Halasa reports grants and nonfinancial support from Sanofi, and Quidel outside the submitted work. Daniel J. Henning reports personal consultant fees from Cytovale and Opticyte. Akram Khan reports grants from United Therapeutics, Johnson & Johnson, 4D Medical, Lung LLC, and Reata Pharmaceuticals, outside the submitted work. Adam S. Lauring reports personal fees from Sanofi and Roche, outside the submitted work. Christopher J. Lindsell reports grants from NIH, DoD, and the Marcus Foundation; contract fees from bioMerieux, Endpoint LLC, and Entegrion Inc, outside the submitted work and has a patent for risk stratification in sepsis and septic shock issued. Emily T. Martin reports personal fees from Pfizer and grants from Merck, outside the submitted work. Arnold S. Monto reports consulting fees from Sanofi-Pasteur and Seqirus outside the submitted work. Ithan D. Peltan reports grants from NIH and Janssen Pharmaceuticals and institutional support from Asahi Kasei Pharma and Regeneron, outside the submitted work. Todd W. Rice reports personal fees from Cumberland Pharmaceuticals, Inc. and personal fees from Avisa Pharma, LLC and Sanofi, outside the submitted work. Wesley H. Self reports consulting fees from Aeprio Pharmaceuticals and Merck outside the submitted work. No other potential conflicts of interest were disclosed.

Background: Given the challenges in implementing widespread testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there is increasing interest in alternative surveillance strategies., Methods: We tested nasopharyngeal swabs from 1094 decedents in the Wayne County Medical Examiner's Office for SARS-CoV-2. All decedents were assessed using a coronavirus disease 2019 (COVID-19) checklist, and decedents flagged using the checklist (298) were preferentially tested. A random sample of decedents not flagged using the checklist were also tested (796). We statistically analyzed the characteristics of decedents (age, sex, race, and manner of death), differentiating between those flagged using the checklist and not and between those SARS-CoV-2-positive and not., Results: A larger percentage of decedents overall were male (70% vs 48%) and black (55% vs 36%) compared with the catchment population. Seven-day average percent positivity among flagged decedents closely matched the trajectory of percent positivity in the catchment population, particularly during the peak of the outbreak (March and April 2020). After a lull in May to mid-June, new positive tests in late June coincided with increased case detection in the catchment. We found large racial disparities in test results; SARS-CoV-2-positive decedents were substantially more likely to be black than SARS-CoV-2-negative decedents (82% vs 51%). SARS-CoV-2-positive decedents were also more likely to be older and to have died of natural causes, including of COVID-19 disease., Conclusions: Disease surveillance through medical examiners and coroners could supplement other forms of surveillance and serve as a possible early outbreak warning sign., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Adults aged ≥65 years are at increased risk for severe outcomes from COVID-19 and were identified as a priority group to receive the first COVID-19 vaccines approved for use under an Emergency Use Authorization (EUA) in the United States (1-3). In an evaluation at 24 hospitals in 14 states,* the effectiveness of partial or full vaccination † with Pfizer-BioNTech or Moderna vaccines against COVID-19-associated hospitalization was assessed among adults aged ≥65 years. Among 417 hospitalized adults aged ≥65 years (including 187 case-patients and 230 controls), the median age was 73 years, 48% were female, 73% were non-Hispanic White, 17% were non-Hispanic Black, 6% were Hispanic, and 4% lived in a long-term care facility. Adjusted vaccine effectiveness (VE) against COVID-19-associated hospitalization among adults aged ≥65 years was estimated to be 94% (95% confidence interval [CI] = 49%-99%) for full vaccination and 64% (95% CI = 28%-82%) for partial vaccination. These findings are consistent with efficacy determined from clinical trials in the subgroup of adults aged ≥65 years (4,5). This multisite U.S. evaluation under real-world conditions suggests that vaccination provided protection against COVID-19-associated hospitalization among adults aged ≥65 years. Vaccination is a critical tool for reducing severe COVID-19 in groups at high risk., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Christopher J. Lindsell reports grants from National Institutes of Health, U.S. Department of Defense, Marcus Foundation, Endpoint Health, Entegrion, bioMerieux, and Bioscape Digital, outside the submitted work. Jay S. Steingrub reports grants from National Institutes of Health, outside the submitted work. Akram Khan reports grants from United Therapeutics, Actelion Pharmaceuticals, Regeneron, and Reata Pharmaceuticals, outside the submitted work. Samuel M. Brown reports grants from National Institutes of Health, U.S. Department of Defense, Intermountain Research and Medical Foundation, and Janssen, and consulting fees paid to his employer from Faron and Sedana, all outside the submitted work. Ithan D. Peltan reports grants from National Institutes of Health and, outside the submitted work, grants from Asahi Kasei Pharma, Janssen Pharmaceuticals, and Regeneron. Adit A. Ginde reports grants from National Institutes of Health, U.S. Department of Defense and AbbVie, outside the submitted work. Carlos G. Grijalva reports consulting fees from Pfizer, Merck, and Sanofi-Pasteur, grants from Campbell Alliance/Syneos Health, National Institutes of Health, Food and Drug Administration, and Agency for Health Care Research and Quality, outside the submitted work. Michelle N. Gong reports grants from National Institutes of Health, Agency for Healthcare Research and Quality, and consulting fees from Regeneron, Philips Healthcare, all outside the submitted work. Steven Y. Chang reports consulting fees from PureTech Health and speaker fees from La Jolla Pharmaceuticals, both outside the submitted work. Jonathan D. Casey reports grants from National Institutes of Health, outside the submitted work. Todd W. Rice reports grants from National Institutes of Health and Endpoint Health, consulting work for Cumberland Pharmaceuticals, Inc, and Sanofi, Inc., outside the submitted work. Manjusha Gaglani reports grants from CDC-Abt Associates, outside the submitted work. Emily T. Martin reports personal fees from Pfizer and grants from Merck, outside the submitted work. Anurag Malani reports shareholder of Pfizer pharmaceuticals. Arnold S. Monto reports personal fees from Sanofi Pasteur and Seqirus, outside the submitted work. Fernanda P. Silveira reports grants from Shire, Qiagen, Ansun, and Novartis, outside the submitted work. Richard K. Zimmerman reports grants from Sanofi Pasteur, outside the submitted work. Donald B. Middleton reports grants and personal fees from Pfizer and personal fees from Seqirus, Sanofi Pasteur, and GlaxoSmithKline, outside the submitted work. No other potential conflicts of interest were disclosed.

Analysis of SARS-CoV-2 genetic diversity within infected hosts can provide insight into the generation and spread of new viral variants and may enable high resolution inference of transmission chains. However, little is known about temporal aspects of SARS-CoV-2 intrahost diversity and the extent to which shared diversity reflects convergent evolution as opposed to transmission linkage. Here we use high depth of coverage sequencing to identify within-host genetic variants in 325 specimens from hospitalized COVID-19 patients and infected employees at a single medical center. We validated our variant calling by sequencing defined RNA mixtures and identified viral load as a critical factor in variant identification. By leveraging clinical metadata, we found that intrahost diversity is low and does not vary by time from symptom onset. This suggests that variants will only rarely rise to appreciable frequency prior to transmission. Although there was generally little shared variation across the sequenced cohort, we identified intrahost variants shared across individuals who were unlikely to be related by transmission. These variants did not precede a rise in frequency in global consensus genomes, suggesting that intrahost variants may have limited utility for predicting future lineages. These results provide important context for sequence-based inference in SARS-CoV-2 evolution and epidemiology., Competing Interests: The authors have declared that no competing interests exist.

We describe a case of chronic coronavirus disease 2019 (COVID-19) in a patient with lymphoma and associated B-cell immunodeficiency. Viral cultures and sequence analysis demonstrate ongoing replication of infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for at least 119 days. The patient had 3 admissions related to COVID-19 over a 4-month period and was treated twice with remdesivir and convalescent plasma with resolution of symptoms. The patient's lack of seroconversion and prolonged course illustrate the importance of humoral immunity in resolving SARS-CoV-2 infection. This case highlights challenges in managing immunocompromised hosts, who may act as persistent shedders and sources of transmission., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)