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The extent to which semi-quantitative antibody levels confer protection against SARS-CoV-2 infection in populations with heterogenous immune histories is unclear. Two nested case-control studies were designed within the multisite HEROES/RECOVER prospective cohort of frontline workers to study the relationship between antibody levels and protection against first-time post-vaccination infection and reinfection with SARS-CoV-2 from December 2021 to January 2023. All participants submitted weekly nasal swabs for rRT-PCR testing and blood samples quarterly and following infection or vaccination. Cases of first-time post-vaccination infection following a third dose of monovalent (origin strain WA-1) mRNA vaccine (n = 613) and reinfection (n = 350) were 1:1 matched to controls based on timing of blood draw and other potential confounders. Conditional logistic regression models were fit to estimate infection risk reductions associated with 3-fold increases in end titers for receptor binding domain (RBD). In first-time post-vaccination and reinfection study samples, most were female (67%, 57%), non-Hispanic (82%, 68%), and without chronic conditions (65%, 65%). The odds of first-time post-vaccination infection were reduced by 21% (aOR = 0.79, 95% CI = [0.66–0.96]) for each 3-fold increase in RBD end titers. The odds of reinfection associated with a 3-fold increase in RBD end titers were reduced by 23% (aOR = 0.77, 95% CI = [0.65–0.92] for unvaccinated individuals and 58% (aOR = 0.42, 95% CI = [0.22–0.84]) for individuals with three mRNA vaccine doses following their first infection. Frontline workers with higher antibody levels following a third dose of mRNA COVID-19 vaccine were at reduced risk of SARS-CoV-2 during Omicron predominance. Among those with previous infections, the point estimates of risk reduction associated with antibody levels was greater for those with three vaccine doses compared to those who were unvaccinated. [ABSTRACT FROM AUTHOR]

Background There are limited data on whether hybrid immunity differs by count and order of immunity-conferring events (infection with severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2] or vaccination against coronavirus disease 2019 [COVID-19]). From a multi-site cohort of frontline workers, we examined the heterogeneity of the effect of hybrid immunity on SARS-CoV-2 antibody levels. Methods Exposures included event count and event order, categorized into 7 permutations. Outcome was level of serum antibodies against receptor-binding domain (RBD) of the ancestral SARS-CoV-2 spike protein (total RBD-binding immunoglobulin). Means were examined up to 365 days after each of the first to seventh events. Results Analysis included 5793 participants measured from 7 August 2020 to 15 April 2023. Hybrid immunity from infection before 1 or 2 vaccine doses elicited modestly superior antibody responses after the second and third events (compared with infections or vaccine doses alone). This superiority was not repeated after additional events. Among adults infected before vaccination, adjusted geometric mean ratios (95% confidence interval [CI]) of anti-RBD early response (versus vaccinated only) were 1.23 (1.14–1.33), 1.09 (1.03–1.14), 0.87 (.81–.94), and 0.99 (.85–1.15) after the second to fifth events, respectively. Post-vaccination infections elicited superior responses; adjusted geometric mean ratios (95% CI) of anti-RBD early response (versus vaccinated only) were 0.93 (.75–1.17), 1.11 (1.06–1.16), 1.17 (1.11–1.24), and 1.20 (1.07–1.34) after the second to fifth events, respectively. Conclusions Evidence of heterogeneity in antibody levels by permutations of infection and vaccination history could inform COVID-19 vaccination policy. [ABSTRACT FROM AUTHOR]

This study used data from the Third National Household and Nutrition Examination Survey (NHANES) to examine the association between pubertal status (Tanner staging for boys and girls and menarche for girls) and alcohol use in a nationally representative sample of youths ages 12 to 17. Logistic regression was used to model the relationship. In general, more advanced pubertal stage was associated with a greater likelihood of having had at least 12 drinks in one's life. In particular, among 12- to 13-year-old boys and girls, higher Tanner scores were associated with increased risk for having already had at least 12 drinks in one's life. Thus, early puberty is associated with having initiated drinking at a young age and therefore may be a marker to help identify a group of youths with whom intervening early regarding alcohol use may be particularly useful. (Contains 5 tables and 2 figures.)

Background Identifying severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections during peripartum hospitalizations is important to guide care, implement prevention measures, and understand infection burden. Methods This cross-sectional analysis used electronic health record data from hospitalizations during which pregnancies ended (peripartum hospitalizations) among a cohort of pregnant persons at 3 US integrated healthcare networks (sites 1–3). Maternal demographic, medical encounter, SARS-CoV-2 testing, and pregnancy and neonatal outcome information was extracted for persons with estimated delivery and pregnancy end dates during March 2020–February 2021 and ≥1 antenatal care record. Site-stratified multivariable logistic regression was used to identify factors associated with testing and compare pregnancy and neonatal outcomes among persons tested. Results Among 17 858 pregnant persons, 10 863 (60.8%) had peripartum SARS-CoV-2 testing; 222/10 683 (2.0%) had positive results. Testing prevalence varied by site and was lower during March–May 2020. Factors associated with higher peripartum SARS-CoV-2 testing odds were Asian race (adjusted odds ratio [aOR]: 1.36; 95% confidence interval [CI]: 1.03–1.79; referent: White) (site 1), Hispanic or Latino ethnicity (aOR: 1.33; 95% CI: 1.08–1.64) (site 2), peripartum Medicaid coverage (aOR: 1.33; 95% CI: 1.06–1.66) (site 1), and preterm hospitalization (aOR: 1.69; 95% CI: 1.19–2.39 [site 1]; aOR: 1.39; 95% CI: 1.03–1.88 [site 2]). Conclusions Findings highlight potential disparities in SARS-CoV-2 peripartum testing by demographic and pregnancy characteristics. Testing practice variations should be considered when interpreting studies relying on convenience samples of pregnant persons testing positive for SARS-CoV-2. Efforts to address testing differences between groups could improve equitable testing practices and care for pregnant persons with SARS-CoV-2 infections. [ABSTRACT FROM AUTHOR]

Background Pregnant individuals are at increased risk of coronavirus disease 2019 (COVID-19) hospitalization and death, and primary and booster COVID-19 vaccination is recommended for this population. Methods Among a cohort of pregnant individuals who received prenatal care at 3 healthcare systems in the United States, we estimated the cumulative incidence of hospitalization with symptomatic COVID-19 illness. We also identified factors associated with COVID-19 hospitalization using a multivariable Cox proportional hazards model with pregnancy weeks as the timescale and a time-varying adjustor that accounted for severe acute respiratory syndrome coronavirus 2 circulation; model covariates included site, age, race, ethnicity, insurance status, prepregnancy weight status, and selected underlying medical conditions. Data were collected primarily through medical record extraction. Results Among 19 456 pregnant individuals with an estimated due date during 1 March 2020–28 February 2021, 75 (0.4%) were hospitalized with symptomatic COVID-19. Factors associated with hospitalization for symptomatic COVID-19 were Hispanic ethnicity (adjusted hazard ratio [aHR], 2.7 [95% confidence interval {CI}, 1.3–5.5]), Native Hawaiian or Pacific Islander race (aHR, 12 [95% CI, 3.2–45.5]), age <25 years (aHR, 3.1 [95% CI, 1.3–7.6]), prepregnancy obesity (aHR, 2.1 [95% CI, 1.1–3.9]), diagnosis of a metabolic disorder (aHR, 2.2 [95% CI, 1.2–3.8]), lung disease excluding asthma (aHR, 49 [95% CI, 28–84]), and cardiovascular disease (aHR, 2.6 [95% CI, 1.5–4.7]). Conclusions Although hospitalization with symptomatic COVID-19 was uncommon, pregnant individuals should be aware of risk factors associated with severe illness when considering COVID-19 vaccination. [ABSTRACT FROM AUTHOR]

Background Data about the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among pregnant individuals are needed to inform infection-prevention guidance and counseling for this population. Methods We prospectively followed a cohort of pregnant individuals during August 2020–March 2021 at 3 US sites. The 3 primary outcomes were incidence rates of any SARS-CoV-2 infection, symptomatic infection, and asymptomatic infection, during pregnancy during periods of SARS-CoV-2 circulation. Participants self-collected weekly midturbinate nasal swabs for SARS-CoV-2 reverse transcription–polymerase chain reaction testing, completed weekly illness symptom questionnaires, and submitted additional swabs with coronavirus disease 2019 (COVID-19)–like symptoms. An overall SARS-CoV-2 infection incidence rate weighted by population counts of women of reproductive age in each state was calculated. Results Among 1098 pregnant individuals followed for a mean of 10 weeks, 9% (99/1098) had SARS-CoV-2 infections during the study. Population-weighted incidence rates of SARS-CoV-2 infection were 10.0 per 1000 (95% confidence interval, 5.7–14.3) person-weeks for any infection, 5.7 per 1000 (1.7–9.7) for symptomatic infections, and 3.5 per 1000 (0–7.1) for asymptomatic infections. Among 96 participants with SARS-CoV-2 infections and symptom data, the most common symptoms were nasal congestion (72%), cough (64%), headache (59%), and change in taste or smell (54%); 28% had measured or subjective fever. Median symptom duration was 10 (interquartile range, 6–16) days. Conclusions Pregnant individuals in this study had a 1% risk of SARS-CoV-2 infection per week, underscoring the importance of COVID-19 vaccination and other prevention measures during pregnancy while SARS-CoV-2 is circulating in the community. [ABSTRACT FROM AUTHOR]

Objective  The aim of the study was to evaluate pregnant women's attitudes toward COVID-19 illness and vaccination and identify factors associated with vaccine acceptability. Study Design  This was a cross-sectional survey among pregnant women enrolled in a prospective COVID-19 cohort study in Salt Lake City, UT, Birmingham, AL, and New York, NY, from August 9 to December 10, 2020. Women were eligible if they were 18 to 50 years old and <28 weeks of gestation. Upon enrollment, women completed surveys regarding concerns about COVID-19 illness and likelihood of getting COVID-19 vaccine if one were available during pregnancy. Vaccine acceptability was defined as a response of "very likely" or "somewhat likely" on a 4-point Likert scale. Factors associated with vaccine acceptability were assessed with multivariable logistic regression. Results  Of 939 pregnant women eligible for the main cohort study, 915 (97%) consented to participate. Among these 915 women, 39% self-identified as White, 23% Black, 33% Hispanic, and 4% Other. Sixty-two percent received an influenza vaccine last season. Seventy-two percent worried about getting sick with COVID-19. If they were to get sick, 92% worried about harm to their pregnancy and 80% about harm to themselves. Only 41% reported they would get a vaccine. Of women who were unlikely to get vaccinated, the most frequently cited concern was vaccine safety for their pregnancy (82%). Non-Hispanic Black and Hispanic women had lower odds of accepting a vaccine compared with non-Hispanic White women (adjusted odds ratios [aOR] 0.4, 95% CI 0.2–0.6 for both). Receipt of influenza vaccine during the previous season was associated with higher odds of vaccine acceptability (aOR 2.1, 95% CI 1.5–3.0). Conclusion  Although most pregnant women worried about COVID-19 illness, <50% were willing to get vaccinated during pregnancy. Racial and ethnic disparities in plans to accept COVID-19 vaccine highlight the need to prioritize strategies to address perceived barriers among groups at high risk for COVID-19. Key Points Less than half of pregnant patients stated they would get a COVID-19 vaccine. Protecting their baby was the most common reason for acceptance and refusal of the COVID-19 vaccine. Patients of minority race/ethnicity and those without prior influenza vaccination were less likely to accept the COVID-19 vaccine. [ABSTRACT FROM AUTHOR]

Background: The Estudio Vacuna de Influenza Peru (VIP) cohort aims to describe the frequency of influenza virus infection, identify predictors of vaccine acceptance, examine the effects of repeated influenza vaccination on immunogenicity, and evaluate influenza vaccine effectiveness among HCP. Methods: The VIP cohort prospectively followed HCP in Lima, Peru, during the 2016‐2018 influenza seasons; a fourth year is ongoing. Participants contribute blood samples before and after the influenza season and after influenza vaccination (for vaccinees). Weekly surveillance is conducted to identify acute respiratory or febrile illnesses (ARFI). When an ARFI is identified, participants self‐collect nasal swabs that are tested for influenza viruses by real‐time reverse transcriptase‐polymerase chain reaction. Influenza vaccination status and 5‐year vaccination history are ascertained. We analyzed recruitment and enrollment results for 2016‐2018 and surveillance participation for 2016‐2017. Results: In the first 3 years of the cohort, VIP successfully contacted 92% of potential participants, enrolled 76% of eligible HCP, and retained >90% of participants across years. About half of participants are medical assistants (54%), and most provide "hands‐on" medical care (76%). Sixty‐nine percent and 52% of participants completed surveillance for >70% of weeks in years 1 and 2, respectively. Fewer weeks of completed surveillance was associated with older age (≥50 years), being a medical assistant, self‐rated health of fair or poor, and not receiving the influenza vaccine during the current season (P‐values <.05). Conclusions: The VIP cohort provides an opportunity to address knowledge gaps about influenza virus infection, vaccination uptake, effectiveness and immunogenicity among HCP. [ABSTRACT FROM AUTHOR]

Background: The Study of Healthcare Personnel with Influenza and other Respiratory Viruses in Israel (SHIRI) prospectively follows a cohort of healthcare personnel (HCP) in two hospitals in Israel. SHIRI will describe the frequency of influenza virus infections among HCP, identify predictors of vaccine acceptance, examine how repeated influenza vaccination may modify immunogenicity, and evaluate influenza vaccine effectiveness in preventing influenza illness and missed work.Methods: Cohort enrollment began in October, 2016; a second year of the study and a second wave of cohort enrollment began in June 2017. The study will run for at least 3 years and will follow approximately 2000 HCP (who are both employees and members of Clalit Health Services [CHS]) with routine direct patient contact. Eligible HCP are recruited using a stratified sampling strategy. After informed consent, participants complete a brief enrollment survey with questions about occupational responsibilities and knowledge, attitudes, and practices about influenza vaccines. Blood samples are collected at enrollment and at the end of influenza season; HCP who choose to be vaccinated contribute additional blood one month after vaccination. During the influenza season, participants receive twice-weekly short message service (SMS) messages asking them if they have acute respiratory illness or febrile illness (ARFI) symptoms. Ill participants receive follow-up SMS messages to confirm illness symptoms and duration and are asked to self-collect a nasal swab. Information on socio-economic characteristics, current and past medical conditions, medical care utilization and vaccination history is extracted from the CHS database. Information about missed work due to illness is obtained by self-report and from employee records. Respiratory specimens from self-collected nasal swabs are tested for influenza A and B viruses, respiratory syncytial virus, human metapneumovirus, and coronaviruses using validated multiplex quantitative real-time reverse transcription polymerase chain reaction assays. The hemagglutination inhibition assay will be used to detect the presence of neutralizing influenza antibodies in serum.Discussion: SHIRI will expand our knowledge of the burden of respiratory viral infections among HCP and the effectiveness of current and repeated annual influenza vaccination in preventing influenza illness, medical utilization, and missed workdays among HCP who are in direct contact with patients.Trial Registration: NCT03331991 . Registered on November 6, 2017. [ABSTRACT FROM AUTHOR]

Despite a longstanding Israel Ministry of Health recommendation that all healthcare personnel (HCP) receive a seasonal influenza vaccine, vaccine uptake among HCP remains below the country's target of 60% coverage. To understand factors related to vaccine hesitancy, we used data from a prospective three-year (2016–2019) influenza vaccine effectiveness study among Israeli HCP to examine knowledge, attitudes, and practices (KAP) about influenza vaccination and their association with vaccine uptake. At the start of each influenza season, all participating HCP completed a questionnaire that included questions about socio-demographic and occupational characteristics, health status, and KAP related to seasonal influenza vaccination. We extracted vaccination history from electronic medical records and employee vaccination registries. We used logistic regression models to identify demographic and occupational factors, and KAP about influenza vaccination, associated with receipt of vaccination. A total of 2,126 HCP were enrolled and had available data on vaccination history. Their median age was 42 years [IQR 35–52], and 73 % self-identified as female. Influenza vaccine uptake in 2016, 2017 and 2018 was 46 %, 48 % and 47 %, respectively. Overall, 36 % of HCP had received an influenza vaccine in ≥ 4 of the eight years prior. HCP aged 35–49 years were less likely to receive influenza vaccine compared to HCP aged ≥ 50 years (OR: 0.81 [95 % CI: 0.67–0.98]). Nurses and allied personnel were less likely to receive influenza vaccine compared to physicians (OR: 0.63 [95 % CI: 0.50–0.78] and OR: 0.53 [95 % CI: 0.40–0.70], respectively). The emotional benefit of vaccination (e.g., anticipating regret if not vaccinated) and the perception of vaccine safety were factors associated with vaccine uptake (OR: 7.60 [95 % CI: 6.27–9.22] and OR: 3.43 [95 % CI:2.91–4.03], respectively). Among HCP at two hospitals in Israel, less than half received an annual influenza vaccine. Older HCP, physicians, and those who reported the emotional benefit of vaccination or agreed that influenza vaccines are safe were more likely to be vaccinated. Future influenza vaccination campaigns could focus on these demographic groups and tailor messages emphasizing the emotional benefits of vaccination and vaccine safety to increase seasonal influenza vaccine uptake among HCP in Israel. [ABSTRACT FROM AUTHOR]

To understand how COVID-19 vaccines impact infection risk in children <5 years, we assessed risk of SARS-CoV-2 infection from Sept 2022-April 2023 in three cohort studies. There was no difference in risk by vaccination status. While vaccines reduce severe disease, they may not reduce SARS-CoV-2 infections in young children., (Published by Oxford University Press on behalf of The Journal of the Pediatric Infectious Diseases Society 2024. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Background: While there is evidence that COVID-19 vaccination protects against development of post-COVID conditions (PCC) after severe infection data are limited on whether vaccination reduces the risk after cases of less-severe non-hospitalized COVID-19 disease with more recent SARS-CoV-2 variant viruses. This study assessed whether COVID-19 vaccination was protective against subsequent development of PCC in persons with predominantly mild initial infections during both Delta and Omicron variant predominance., Methods: This study utilized a case-control design, nested within the HEROES-RECOVER cohort. Participants aged ≥18 years with PCR-confirmed SARS-CoV-2 infection between 6/28/2021 and 9/14/2022 were surveyed for PCC, defined by symptoms lasting >1 month after initial infection Cases were participants self-reporting PCC and controls were participants that did not self-report PCC. The exposure was mRNA COVID-19 vaccination (2 or 3 monovalent doses) versus no COVID-19 vaccination. Logistic regression was used to compare the odds of PCC among vaccinated and unvaccinated persons; additional analyses evaluating PCC subtypes were also performed., Results: A total of 936 participants with documented SARS-CoV-2 infection were included; of these 23.6% (221) reported PCC and 83.3% (779) were vaccinated. Participants who received a 3rd COVID-19 monovalent mRNA dose prior to infection had lower odds of PCC-related gastrointestinal, neurological, and other symptoms compared to unvaccinated participants (aOR: 0.37; 95% CI: 0.16-0.85; aOR: 0.56; 95% CI: 0.32-0.97; aOR:0.48; 95% CI: 0.25-0.91)., Conclusions: COVID-19 vaccination protected against development of PCC among persons with mild infection during both Delta and Omicron variant predominance, supporting vaccination as an important tool for PCC prevention., (Published by Oxford University Press on behalf of Infectious Diseases Society of America 2024.)

Background: Previous estimates of vaccine effectiveness (VE) against asymptomatic influenza virus infection based on seroconversion have varied widely and may be biased. We estimated 2022-2023 influenza VE against illness and asymptomatic infection in a prospective cohort., Methods: In the HEROES-RECOVER cohort, adults at increased occupational risk of influenza exposure across 7 US sites provided weekly symptom reports and nasal swabs for reverse transcription-polymerase chain reaction (RT-PCR) influenza testing. Laboratory-confirmed influenza virus infections were classified as symptomatic (≥1 symptom) or asymptomatic during the week of testing. Participants reported demographic information and vaccination through surveys; most sites verified vaccination through medical record and immunization registry review. Person-time was calculated as days from the site-specific influenza season start (September-October 2022) through date of infection, study withdrawal, or season end (May 2023). We compared influenza incidence among vaccinated versus unvaccinated participants overall, by symptom status, and by influenza A subtype, using Cox proportional hazards regression adjusted for site and occupation. We estimated VE as (1 - adjusted hazard ratio) × 100%., Results: In total, 269 of 3785 (7.1%) participants had laboratory-confirmed influenza, including 263 (98%) influenza A virus infections and 201 (75%) symptomatic illnesses. Incidence of laboratory-confirmed influenza illness among vaccinated versus unvaccinated participants was 23.7 and 33.2 episodes per 100 000 person-days, respectively (VE: 38%; 95% CI: 15%-55%). Incidence of asymptomatic influenza virus infection was 8.0 versus 11.6 per 100 000 (VE: 13%; 95% CI: -47%, 49%)., Conclusions: Vaccination reduced incidence of symptomatic but not asymptomatic influenza virus infection, suggesting that influenza vaccination attenuates progression from infection to illness., Competing Interests: Potential conflicts of interest . A. N., L. J. E., J. D., H. T., G. N.-A., K. D. E., K. L., J. L. B., A. L. P., A. C.-M., and L. O. report funding from the CDC, Westat, or Abt Associates related to the current manuscript. M. G. reports grants from CDC, Westat, and Vanderbilt University Medical Center and participation on the Texas Pediatric Society, Texas Chapter of the American Academy of Pediatrics Infectious Diseases and Immunization Committee as co-chair. S. K. Y. and A. L. P. report a contract from Novavax, Inc, for unrelated studies. M. T. has consulted for Novavax and CSL Seqirus. A. C.-M. reports funding from the state of Florida for the Firefighter Cancer Initiative and a leadership role in the International Commission on Occupational Health. 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. Data availability . For questions about data availability, please contact the corresponding author., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

BackgroundHealthcare personnel (HCP) are at high risk for respiratory infections through occupational exposure to respiratory viruses.AimWe used data from a prospective influenza vaccine effectiveness study in HCP to quantify the incidence of acute respiratory infections (ARI) and their associated presenteeism and absenteeism.MethodsAt the start and end of each season, HCP at two Israeli hospitals provided serum to screen for antibodies to influenza virus using the haemagglutination inhibition assay. During the season, active monitoring for the development of ARI symptoms was conducted twice a week by RT-PCR testing of nasal swabs for influenza and respiratory syncytial virus (RSV). Workplace presenteeism and absenteeism were documented. We calculated incidences of influenza- and RSV-associated ARI and applied sampling weights to make estimates representative of the source population.ResultsThe median age of 2,505 participating HCP was 41 years, and 70% were female. Incidence was 9.1 per 100 person-seasons (95% CI: 5.8-14.2) for RT-PCR-confirmed influenza and 2.5 per 100 person-seasons (95% CI: 0.9-7.1) for RSV illness. Each season, 18-23% of unvaccinated and influenza-negative HCP seroconverted. The incidence of seroconversion or RT-PCR-confirmed influenza was 27.5 per 100 person-seasons (95% CI: 17.8-42.5). Work during illness occurred in 92% (95% CI: 91-93) of ARI episodes, absence from work in 38% (95% CI: 36-40).ConclusionInfluenza virus and RSV infections and associated presenteeism and absenteeism were common among HCP. Improving vaccination uptake among HCP, infection control, and encouraging sick HCP to stay home are important strategies to reduce ARI incidence and decrease the risk of in-hospital transmission.

Hybrid immunity, as a result of infection and vaccination to SARS-CoV-2, has been well studied in adults but limited evidence is available in children. We evaluated the antibody responses to primary SARS-CoV-2 infection among vaccinated and unvaccinated children aged ≥ 5 years., Methods: A longitudinal cohort study of children aged ≥ 5 was conducted during August 2021-August 2022, at sites in Arizona, Texas, Utah, and Florida. Children submitted weekly nasal swabs for PCR testing and provided sera 14-59 days after PCR-confirmed SARS-CoV-2 infection. Antibodies were measured by ELISA against the receptor-binding domain (RBD) and S2 domain of ancestral Spike (WA1), in addition to Omicron (BA.2) RBD, following infection in children, with and without prior monovalent ancestral mRNA COVID-19 vaccination., Results: Among the 257 participants aged 5 to 18 years, 166 (65%) had received at least two mRNA COVID-19 vaccine doses ≥ 14 days prior to infection. Of these, 53 occurred during Delta predominance, with 37 (70%) unvaccinated at the time of infection. The remaining 204 infections occurred during Omicron predominance, with 53 (26%) participants unvaccinated. After adjusting for weight, age, symptomatic infection, and gender, significantly higher mean RBD AUC values were observed among the vaccinated group compared to the unvaccinated group for both WA1 and Omicron ( p < 0.0001). A smaller percentage of vaccinated children reported fever during illness, with 55 (33%) reporting fever compared to 44 (48%) unvaccinated children reporting fever ( p = 0.021)., Conclusions: Children with vaccine-induced immunity at the time of SARS-CoV-2 infection had higher antibody levels during convalescence and experienced less fever compared to unvaccinated children during infection.

Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Manjusha Gaglani reports being co-chair of the Infectious Diseases and Immunization Committee, Texas Pediatric Society and support from Janssen for a respiratory syncytial virus birth cohort observational study. No other potential conflicts of interest were disclosed.

Background: We conducted a cross-sectional study of pregnant women with acute respiratory illness during delivery hospitalizations during influenza season to describe clinical testing for respiratory viruses and infection prevention practices., Methods: Women had nasal swabs tested for influenza and other respiratory viruses. Among 91 enrolled women, 22 (24%) had clinical testing for influenza., Results: Based on clinical and study testing combined, 41 of 91 (45%) women had samples positive for respiratory viruses. The most common virus was influenza (17 of 91, 19%); 53% (9 of 17) of influenza virus infections were identified through study testing alone. Only 16% of women were on droplet precautions., Conclusions: Peripartum respiratory infections may be underrecognized., (Published by Oxford University Press for the Infectious Diseases Society of America 2021.)