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Background: Asymptomatic SARS-CoV-2 infection in children is highly prevalent but its acute and chronic implications have been minimally described., Methods: In this controlled case-ascertained household transmission study, we recruited asymptomatic children <18 years with SARS-CoV-2 nucleic acid testing performed at 12 tertiary care pediatric institutions in Canada and the United States. We attempted to recruit all test-positive children and 1 to 3 test-negative, site-matched controls. After 14 days' follow-up we assessed the clinical (ie, symptomatic) and combined (ie, test-positive, or symptomatic) secondary attack rates (SARs) among household contacts. Additionally, post-COVID-19 condition (PCC) was assessed in SARS-CoV-2-positive participating children after 90 days' follow-up., Results: A total of 111 test-positive and 256 SARS-CoV-2 test-negative asymptomatic children were enrolled between January 2021 and April 2022. After 14 days, excluding households with co-primary cases, the clinical SAR among household contacts of SARS-CoV-2-positive and -negative index children was 10.6% (19/179; 95% CI: 6.5%-16.1%) and 2.0% (13/663; 95% CI: 1.0%-3.3%), respectively (relative risk = 5.4; 95% CI: 2.7-10.7). In households with a SARS-CoV-2-positive index child, age <5 years, being pre-symptomatic (ie, developed symptoms after test), and testing positive during Omicron and Delta circulation periods (vs earlier) were associated with increased clinical and combined SARs among household contacts. Among 77 asymptomatic SARS-CoV-2-infected children with 90-day follow-up, 6 (7.8%; 95% CI: 2.9%-16.2%) reported PCC., Conclusions: Asymptomatic SARS-CoV-2-infected children, especially those <5 years, are important contributors to household transmission, with 1 in 10 exposed household contacts developing symptomatic illness within 14 days. Asymptomatic SARS-CoV-2-infected children may develop PCC., Competing Interests: Potential conflicts of interest . A. F. reports grants from the University of Calgary Eyes High Postdoctoral Fellowship and Canadian Institutes of Health Research Banting Postdoctoral Fellowship, and support for meetings and/or travel from a Trainee Travel Grant (Pediatric Academic Societies and Trainee travel grant), Alberta Children's Hospital Association, University of Calgary. L. A. reports grants from Pfizer. M. W. reports support for meetings and/or travel from US Acute Care Solutions (USACS), stock and a board of directors position for EM Device Lab. N. K. reports a leadership or fiduciary role for the Pediatric Emergency Care Applied Research, Pediatric Emergency Research Network; research funding from the National Institutes of Health (NIH), Health Resources and Services Administration (HRSA), and Patient-Centered Outcomes Research Institute (PCORI). R. M. reports royalties or licenses for Affinivax; consulting fees from GSK, Affinivax, and Merck; payment for lectures and support for meetings and/or travel from GSK; patents planned, issued, or pending for Boston Children's Hospital; being a member of the Affinivax board of directors; and stock options for Affinivax and Corner Therapeutics. S. M. M. reports grants from Sanofi, Merck, Pfizer National Minority Quality Forum (US); support for meetings and/or travel from Sanofi, Merck, GSK, Pfizer, CSL, Biosciences Association of Manitoba (BAM), and the National Minority Quality Forum (US); and participation on a Data and Safety Monitoring Board or Advisory board for Sanofi. T. A. F. reports grants from the National Heart, Lung, and Blood Institute (NHLBI) and leadership or fiduciary roles for the Society of Pediatric Research and the Pediatric Academic Societies. 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) 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.)

The emergence of many presymptomatic hidden transmission events significantly complicated the intervention and control of the spread of COVID-19 in the USA during the year 2020. To analyze the role that presymptomatic infections play in the spread of this disease, we developed a state-level metapopulation model to simulate COVID-19 transmission in the USA in 2020 during which period the number of confirmed cases was more than in any other country. We estimated that the transmission rate (i.e., the number of new infections per unit time generated by an infected individual) of presymptomatic infections was approximately 59.9% the transmission rate of reported infections. We further estimated that {at any point in time the} average proportion of infected individuals in the presymptomatic stage was consistently over 50% of all infected individuals. Presymptomatic transmission was consistently contributing over 52% to daily new infections, as well as consistently contributing over 50% to the effective reproduction number from February to December. Finally, non-pharmaceutical intervention targeting presymptomatic infections was very effective in reducing the number of reported cases. These results reveal the significant contribution that presymptomatic transmission made to COVID-19 transmission in the USA during 2020, as well as pave the way for the design of effective disease control and mitigation strategies.

Background: Low-density asymptomatic Plasmodium infections are prevalent in endemic areas, but little is known about their natural history. The trajectories of these infections and their propensity to fluctuate to undetectable densities can affect detection in clinical trials and field studies. We aimed to classify the natural history of these infections in a high transmission area over 29 days., Methods: In this longitudinal cohort study, we enrolled healthy, malaria-asymptomatic, afebrile, adults (age 18-59 years) and older children (age 8-17 years) in Katakwi District, Uganda, who were negative for Plasmodium infection on rapid diagnostic tests. Participants were instructed to self-collect one dried blood spot (DBS) per day for a maximum of 29 days. We excluded people if they were pregnant or taking antimalarials. During weekly clinic visits, staff collected a DBS and a 4 mL sample of venous blood. We analysed DBSs by Plasmodium 18S rRNA quantitative RT-PCR (qRT-PCR). We classified DBS by infection type as negative, P falciparum, non-P falciparum, or mixed. We plotted infection type over time for each participant and categorised trajectories as negative, new, cleared, chronic, or indeterminate infections. To estimate the effect of single timepoint sampling, we calculated the daily prevalence for each study day and estimated the number of infections that would have been detected in our population if sampling frequency was reduced., Findings: Between April 9 and May 20, 2021, 3577 DBSs were collected by 128 (40 male adults, 60 female adults, 12 male children, and 16 female children) study participants. 2287 (64%) DBSs were categorised as negative, 751 (21%) as positive for P falciparum, 507 (14%) as positive for non-P falciparum, and 32 (1%) as mixed infections. Daily Plasmodium prevalence in the population ranged from 45·3% (95% CI 36·6-54·1) at baseline to 30·3% (21·9-38·6) on day 24. 37 (95%) of 39 P falciparum and 35 (85%) of 41 non-P falciparum infections would have been detected with every other day sampling, whereas, with weekly sampling, 35 (90%) P falciparum infections and 31 (76%) non-P falciparum infections would have been detected., Interpretation: Parasite dynamics and species are highly variable among low-density asymptomatic Plasmodium infections. Sampling every other day or every 3 days detected a similar proportion of infections as daily sampling, whereas testing once per week or even less frequently could misclassify up to a third of the infections. Even using highly sensitive diagnostics, single timepoint testing might misclassify the true infection status of an individual., Funding: US National Institutes of Health and Bill and Melinda Gates Foundation., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Importance: Data on the epidemiology of mild to moderately severe COVID-19 are needed to inform public health guidance., Objective: To evaluate associations between 2 or 3 doses of mRNA COVID-19 vaccine and attenuation of symptoms and viral RNA load across SARS-CoV-2 viral lineages., Design, Setting, and Participants: A prospective cohort study of essential and frontline workers in Arizona, Florida, Minnesota, Oregon, Texas, and Utah with COVID-19 infection confirmed by reverse transcriptase-polymerase chain reaction testing and lineage classified by whole genome sequencing of specimens self-collected weekly and at COVID-19 illness symptom onset. This analysis was conducted among 1199 participants with SARS-CoV-2 from December 14, 2020, to April 19, 2022, with follow-up until May 9, 2022, reported., Exposures: SARS-CoV-2 lineage (origin strain, Delta variant, Omicron variant) and COVID-19 vaccination status., Main Outcomes and Measures: Clinical outcomes included presence of symptoms, specific symptoms (including fever or chills), illness duration, and medical care seeking. Virologic outcomes included viral load by quantitative reverse transcriptase-polymerase chain reaction testing along with viral viability., Results: Among 1199 participants with COVID-19 infection (714 [59.5%] women; median age, 41 years), 14.0% were infected with the origin strain, 24.0% with the Delta variant, and 62.0% with the Omicron variant. Participants vaccinated with the second vaccine dose 14 to 149 days before Delta infection were significantly less likely to be symptomatic compared with unvaccinated participants (21/27 [77.8%] vs 74/77 [96.1%]; OR, 0.13 [95% CI, 0-0.6]) and, when symptomatic, those vaccinated with the third dose 7 to 149 days before infection were significantly less likely to report fever or chills (5/13 [38.5%] vs 62/73 [84.9%]; OR, 0.07 [95% CI, 0.0-0.3]) and reported significantly fewer days of symptoms (10.2 vs 16.4; difference, -6.1 [95% CI, -11.8 to -0.4] days). Among those with Omicron infection, the risk of symptomatic infection did not differ significantly for the 2-dose vaccination status vs unvaccinated status and was significantly higher for the 3-dose recipients vs those who were unvaccinated (327/370 [88.4%] vs 85/107 [79.4%]; OR, 2.0 [95% CI, 1.1-3.5]). Among symptomatic Omicron infections, those vaccinated with the third dose 7 to 149 days before infection compared with those who were unvaccinated were significantly less likely to report fever or chills (160/311 [51.5%] vs 64/81 [79.0%]; OR, 0.25 [95% CI, 0.1-0.5]) or seek medical care (45/308 [14.6%] vs 20/81 [24.7%]; OR, 0.45 [95% CI, 0.2-0.9]). Participants with Delta and Omicron infections who received the second dose 14 to 149 days before infection had a significantly lower mean viral load compared with unvaccinated participants (3 vs 4.1 log10 copies/μL; difference, -1.0 [95% CI, -1.7 to -0.2] for Delta and 2.8 vs 3.5 log10 copies/μL, difference, -1.0 [95% CI, -1.7 to -0.3] for Omicron)., Conclusions and Relevance: In a cohort of US essential and frontline workers with SARS-CoV-2 infections, recent vaccination with 2 or 3 mRNA vaccine doses less than 150 days before infection with Delta or Omicron variants, compared with being unvaccinated, was associated with attenuated symptoms, duration of illness, medical care seeking, or viral load for some comparisons, although the precision and statistical significance of specific estimates varied.

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., (Published by Oxford University Press for the Infectious Diseases Society of America 2021.)

Importance: Approximately 1 in 5 adults in the US had a sexually transmitted infection (STI) in 2018. This review provides an update on the epidemiology, diagnosis, and treatment of gonorrhea, chlamydia, syphilis, Mycoplasma genitalium, trichomoniasis, and genital herpes., Observations: From 2015 to 2019, the rates of gonorrhea, chlamydia, and syphilis increased in the US; from 1999 to 2016, while the rates of herpes simplex virus type 1 (HSV-1) and HSV-2 declined. Populations with higher rates of STIs include people younger than 25 years, sexual and gender minorities such as men and transgender women who have sex with men, and racial and ethnic minorities such as Black and Latinx people. Approximately 70% of infections with HSV and trichomoniasis and 53% to 100% of extragenital gonorrhea and chlamydia infections are asymptomatic or associated with few symptoms. STIs are associated with HIV acquisition and transmission and are the leading cause of tubal factor infertility in women. Nucleic acid amplification tests have high sensitivities (86.1%-100%) and specificities (97.1%-100%) for the diagnosis of gonorrhea, chlamydia, M genitalium, trichomoniasis, and symptomatic HSV-1 and HSV-2. Serology remains the recommended method to diagnose syphilis, typically using sequential testing to detect treponemal and nontreponemal (antiphospholipid) antibodies. Ceftriaxone, doxycycline, penicillin, moxifloxacin, and the nitroimidazoles, such as metronidazole, are effective treatments for gonorrhea, chlamydia, syphilis, M genitalium, and trichomoniasis, respectively, but antimicrobial resistance limits oral treatment options for gonorrhea and M genitalium. No cure is available for genital herpes. Effective STI prevention interventions include screening, contact tracing of sexual partners, and promoting effective barrier contraception., Conclusions and Relevance: Approximately 1 in 5 adults in the US had an STI in 2018. Rates of gonorrhea, chlamydia, and syphilis in the US have increased, while rates of HSV-1 and HSV-2 have declined. Ceftriaxone, doxycycline, penicillin, moxifloxacin, and the nitroimidazoles are effective treatments for gonorrhea, chlamydia, syphilis, Mycoplasma genitalium, and trichomoniasis, respectively, but antimicrobial resistance limits oral therapies for gonorrhea and Mycoplasma genitalium, and no cure is available for genital herpes.

We consider epidemiological modeling for the design of COVID-19 interventions in university populations, which have seen significant outbreaks during the pandemic. A central challenge is sensitivity of predictions to input parameters coupled with uncertainty about these parameters. Nearly 2 y into the pandemic, parameter uncertainty remains because of changes in vaccination efficacy, viral variants, and mask mandates, and because universities' unique characteristics hinder translation from the general population: a high fraction of young people, who have higher rates of asymptomatic infection and social contact, as well as an enhanced ability to implement behavioral and testing interventions. We describe an epidemiological model that formed the basis for Cornell University's decision to reopen for in-person instruction in fall 2020 and supported the design of an asymptomatic screening program instituted concurrently to prevent viral spread. We demonstrate how the structure of these decisions allowed risk to be minimized despite parameter uncertainty leading to an inability to make accurate point estimates and how this generalizes to other university settings. We find that once-per-week asymptomatic screening of vaccinated undergraduate students provides substantial value against the Delta variant, even if all students are vaccinated, and that more targeted testing of the most social vaccinated students provides further value., Competing Interests: The authors declare no competing interest., (Copyright © 2021 the Author(s). Published by PNAS.)

Background: Several vaccines are now available under emergency use authorization in the United States and have demonstrated efficacy against symptomatic COVID-19. Vaccine impact on asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is largely unknown., Methods: We conducted a retrospective cohort study of consecutive, asymptomatic adult patients (n = 39 156) within a large US healthcare system who underwent 48 333 preprocedural SARS-CoV-2 molecular screening tests between 17 December 2020 and 8 February 2021. The primary exposure of interest was vaccination with ≥1 dose of an mRNA COVID-19 vaccine. The primary outcome was relative risk (RR) of a positive SARS-CoV-2 molecular test among those asymptomatic persons who had received ≥1 dose of vaccine compared with persons who had not received vaccine during the same time period. RR was adjusted for age, sex, race/ethnicity, patient residence relative to the hospital (local vs nonlocal), healthcare system regions, and repeated screenings among patients using mixed-effects log-binomial regression., Results: Positive molecular tests in asymptomatic individuals were reported in 42 (1.4%) of 3006 tests and 1436 (3.2%) of 45 327 tests performed on vaccinated and unvaccinated patients, respectively (RR, .44; 95% CI, .33-.60; P < .0001). Compared with unvaccinated patients, risk of asymptomatic SARS-CoV-2 infection was lower among those >10 days after the first dose (RR, .21; 95% CI, .12-.37; P < .0001) and >0 days after the second dose (RR, .20; 95% CI, .09-.44; P < .0001) in the adjusted analysis., Conclusions: COVID-19 vaccination with an mRNA-based vaccine showed a significant association with reduced risk of asymptomatic SARS-CoV-2 infection as measured during preprocedural molecular screening. Results of this study demonstrate the impact of the vaccines on reduction in asymptomatic infections supplementing the randomized trial results on symptomatic patients., (© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America.)

Background: Many patients with coronavirus disease 2019 (COVID-19) are asymptomatic. The prevalence of COVID-19 in orthopaedic populations will vary depending on the time and place where the sampling is performed. The idea that asymptomatic carriers play a role is generalizable but has not been studied in large populations of patients undergoing elective orthopaedic surgery. We therefore evaluated this topic in one large, metropolitan city in a state that had the ninth-most infections in the United States at the time this study was completed (June 2020). This work was based on a screening and testing protocol that required all patients to be tested for COVID-19 preoperatively., Questions/purposes: (1) What is the prevalence of asymptomatic COVID-19 infection in patients planning to undergo orthopaedic surgery in one major city, in order to provide other surgeons with a framework for assessing COVID-19 rates in their healthcare system? (2) How did patients with positive test results for COVID-19 differ in terms of age, sex, and orthopaedic conditions? (3) What proportion of patients had complications treated, and how many patients had a symptomatic COVID-19 infection within 30 days of surgery (recognizing that some may have been missed and so our estimates of event rates will necessarily underestimate the frequency of this event)?, Methods: All adult patients scheduled for surgery at four facilities (two tertiary care hospitals, one orthopaedic specialty hospital, and one ambulatory surgery center) at a single institution in the Philadelphia metropolitan area from April 27, 2020 to June 12, 2020 were included in this study. A total of 1295 patients were screened for symptoms, exposure, temperature, and oxygen saturation via a standardized protocol before surgical scheduling; 1.5% (19 of 1295) were excluded because they had COVID-19 symptoms, exposure, or recent travel based on the initial screening questionnaire, leaving 98.5% (1276 of 1295) who underwent testing for COVID-19 preoperatively. All 1276 patients who passed the initial screening test underwent nasopharyngeal swabbing for COVID-19 via reverse transcription polymerase chain reaction before surgery. The mean age at the time of testing was 56 ± 16 years, and 53% (672 of 1276) were men. Eighty-seven percent (1106), 8% (103), and 5% (67) were tested via the Roche, Abbott, and Cepheid assays, respectively. All patients undergoing elective surgery were tested via the Roche assay, while those undergoing nonelective surgery received either the Abbott or Cepheid assay, based on availability. Patients with positive test results undergoing elective surgery had their procedures rescheduled, while patients scheduled for nonelective surgery underwent surgery regardless of their test results. Additionally, we reviewed the records of all patients at 30 days postoperatively for emergency room visits, readmissions, and COVID-19-related complications via electronic medical records and surgeon-reported complications. However, we had no method for definitively determining how many patients had complications, emergency department visits, or readmissions outside our system, so our event rate estimates for these endpoints are necessarily best-case estimates., Results: A total of 0.5% (7 of 1276) of the patients tested positive for COVID-19: five via the Roche assay and two via the Abbott assay. Patients with positive test results were younger than those with negative results (39 ± 12 years versus 56 ± 16 years; p = 0.01). With the numbers available, we found no difference in the proportion of patients with positive test results for COVID-19 based on subspecialty area (examining the lowest and highest point estimates, respectively, we observed: trauma surgery [3%; 2 of 68 patients] versus hip and knee [0.3%; 1 of 401 patients], OR 12 [95% CI 1-135]; p = 0.06). No patients with negative preoperative test results for COVID-19 developed a symptomatic COVID-19 infection within 30 days postoperatively. Within 30 days of surgery, 0.9% (11 of 1276) of the patients presented to the emergency room, and 1.3% (16 of 1276) were readmitted for non-COVID-19-related complications. None of the patients with positive test results for COVID-19 preoperatively experienced complications. However, because some were likely treated outside our healthcare system, the actual percentages may be higher., Conclusion: Because younger patients are more likely to be asymptomatic carriers of disease, surgeons should emphasize the importance of taking proper precautions to prevent virus exposure preoperatively. Because the rates of COVID-19 infection differ based on city and time, surgeons should monitor the local prevalence of disease to properly advise patients on the risk of COVID-19 exposure. Further investigation is required to assess the prevalence in the orthopaedic population in cities with larger COVID-19 burdens., Level of Evidence: Level III, therapeutic study., Competing Interests: Each author certifies that neither he nor she, nor any member of his or her immediate family, has funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request., (Copyright © 2021 by the Association of Bone and Joint Surgeons.)

Objective: To describe the frequency and timing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody detection in a convenience sample of skilled nursing facility (SNF) residents with and without confirmed SARS-CoV-2 infection., Design: Retrospective analysis of SNF electronic health records., Setting: Qualitative SARS-CoV-2 antibody test results were available from 81 SNFs in 16 states., Participants: Six hundred and sixty nine SNF residents who underwent both polymerase chain reaction (PCR) and antibody testing for SARS-CoV-2., Measurements: Presence of SARS-CoV-2 antibodies following the first positive PCR test for confirmed cases, or first PCR test for non-cases., Results: Among 397 residents with PCR-confirmed infection, antibodies were detected in 4 of 7 (57.1%) tested within 7-14 days of their first positive PCR test; in 44 of 47 (93.6%) tested within 15-30 days; in 182 of 219 (83.1%) tested within 31-60 days; and in 110 of 124 (88.7%) tested after 60 days. Among 272 PCR negative residents, antibodies were detected in 2 of 9 (22.2%) tested within 7-14 days of their first PCR test; in 41 of 81 (50.6%) tested within 15-30 days; in 65 of 148 (43.9%) tested within 31-60 days; and in 9 of 34 (26.5%) tested after 60 days. No significant differences in baseline resident characteristics or symptoms were observed between those with versus without antibodies., Conclusions: These findings suggest that vulnerable older adults can mount an antibody response to SARS-CoV-2, and that antibodies are most likely to be detected within 15-30 days of diagnosis. That antibodies were detected in a large proportion of residents with no confirmed SARS-CoV-2 infection highlights the complexity of identifying who is infected in real time. Frequent surveillance and diagnostic testing based on low thresholds of clinical suspicion for symptoms and/or exposure will remain critical to inform strategies designed to mitigate outbreaks in SNFs while community SARS-CoV-2 prevalence remains high., (© 2021 The American Geriatrics Society.)

Importance: A significant proportion of COVID-19 transmission occurs silently during the presymptomatic and asymptomatic stages of infection. Children, although important drivers of silent transmission, are not included in the current COVID-19 vaccination campaigns., Objective: To estimate the benefits of identifying silent infections among children as a proxy for their vaccination., Design, Setting, and Participants: This study used an age-structured disease transmission model, parameterized with census data and estimates from published literature, to simulate the estimated synergistic effect of interventions in reducing attack rates during the course of 1 year among a synthetic population representative of the US demographic composition. The population included 6 age groups of 0 to 4, 5 to 10, 11 to 18, 19 to 49, 50 to 64, and 65 years or older based on US census data. Data were analyzed from December 12, 2020, to February 26, 2021., Exposures: In addition to the isolation of symptomatic cases within 24 hours of symptom onset, vaccination of adults was implemented to reach a 40% to 60% coverage during 1 year with an efficacy of 95% against symptomatic and severe COVID-19., Main Outcomes and Measures: The combinations of proportion and speed for detecting silent infections among children that would suppress future attack rates to less than 5%., Results: In the base-case scenarios with an effective reproduction number Re = 1.2, a targeted approach that identifies 11% of silent infections among children within 2 days and 14% within 3 days after infection would bring attack rates to less than 5% with 40% vaccination coverage of adults. If silent infections among children remained undetected, achieving the same attack rates would require an unrealistically high vaccination coverage (≥81%) of this age group, in addition to 40% vaccination coverage of adults. The estimated effect of identifying silent infections was robust in sensitivity analyses with respect to vaccine efficacy against infection and reduced susceptibility of children to infection., Conclusions and Relevance: In this simulation modeling study of a synthetic US population, in the absence of vaccine availability for children, a targeted approach to rapidly identify silent COVID-19 infections in this age group was estimated to significantly mitigate disease burden. These findings suggest that without measures to interrupt transmission chains from silent infections, vaccination of adults is unlikely to contain the outbreaks in the near term.

Introduction: Healthcare workers (HCW) treating COVID-19 patients are at high risk for infection and may also spread infection through their contact with vulnerable patients. Smell loss has been associated with SARS-CoV-2 infection, but it is unknown whether monitoring for smell loss can be used to identify asymptomatic infection among high risk individuals. In this study we sought to determine if tracking smell sensitivity and loss using an at-home assessment could identify SARS-CoV-2 infection in HCW., Methods and Findings: We performed a prospective cohort study tracking 473 HCW across three months to determine if smell loss could predict SARS-CoV-2 infection in this high-risk group. HCW subjects completed a longitudinal, behavioral at-home assessment of olfaction with household items, as well as detailed symptom surveys that included a parosmia screening questionnaire, and real-time quantitative polymerase chain reaction testing to identify SARS-CoV-2 infection. Our main measures were the prevalence of smell loss in SARS-CoV-2-positive HCW versus SARS-CoV-2-negative HCW, and timing of smell loss relative to SARS-CoV-2 test positivity. SARS-CoV-2 was identified in 17 (3.6%) of 473 HCW. HCW with SARS-CoV-2 infection were more likely to report smell loss than SARS-CoV-2-negative HCW on both the at-home assessment and the screening questionnaire (9/17, 53% vs 105/456, 23%, P < .01). 6/9 (67%) of SARS-CoV-2-positive HCW reporting smell loss reported smell loss prior to having a positive SARS-CoV-2 test, and smell loss was reported a median of two days before testing positive. Neurological symptoms were reported more frequently among SARS-CoV-2-positive HCW who reported smell loss compared to those without smell loss (9/9, 100% vs 3/8, 38%, P < .01)., Conclusions: In this prospective study of HCW, self-reported changes in smell using two different measures were predictive of SARS-CoV-2 infection. Smell loss frequently preceded a positive test and was associated with neurological symptoms., Competing Interests: The authors have declared that no competing interests exist.

Search and find methods *) such as cluster tracing 1)-6) or large-scale PCR testing **) of those who exhibit no symptoms or only mild symptoms of COVID-19 is shown by data analysis to be a powerful means to suppress the spread of COVID-19 instead of, or in addition to, lockdown of the entire population. Here we investigate this issue by analyzing the data from some cities and countries and we establish that search and find method is as powerful as lockdown of a city or a country. Moreover, in contrast to lockdown, it neither causes inconvenience to citizens nor does it disrupt the economy. Generally speaking, it is advisable that both social distancing and increased test numbers be employed to suppress spread of the virus. The product of the total test number with the rate of positive cases is the crucial index.

A Veterans Affairs long term care facility on Long Island New York was confronted with a COVID-19 outbreak in late March to Mid-April 2020. Faced with a dwindling supply of PPE, the Infection Control team distributed supplies saved for a possible Ebola outbreak. A COVID unit was created within the nursing home facilitating the geographic isolation of cases; universal testing of residents and employees allowed for the implementation of proper quarantine measures. It was a multidisciplinary team approach led by the Infection Control team that successfully contained this outbreak., (Copyright © 2020 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.)

Objective: This study aimed to explore the transmission of COVID-19 in a U.S. state psychiatric hospital setting., Methods: Symptomatic and asymptomatic patients were tested throughout a large psychiatric hospital to determine penetrance. The hospital followed initial Centers for Disease Control and Prevention (CDC) guidelines., Results: Seventy-eight percent (N=51 of 65) of tested patients in the building where the first positive patient was housed (building zero) tested positive for COVID-19. Eighty-eight percent (N=14 of 16) of tested asymptomatic patients in building zero were positive, compared with 12% (N=6 of 51) of randomly selected asymptomatic patients in a sample from the rest of the hospital., Conclusions: A high percentage of patients can become positive for COVID-19 despite following initial CDC guidelines. As such, use of masks by all patients in close-quarter settings prior to the first positive case appears warranted. Recent CDC guidelines align with this strategy.

Sickle cell disease (SCD) disproportionately affects Black or African American persons in the United States and can cause multisystem organ damage and reduced lifespan. Among 178 persons with SCD in the United States who were reported to an SCD-coronavirus disease case registry, 122 (69%) were hospitalized and 13 (7%) died.

Adolescents account for most undiagnosed HIV infections in the United States. Although the Centers for Disease Control and Prevention (CDC) recommends universal HIV screening for all patients ≥13 years, <10% of adolescents have been tested for HIV. To identify earlier opportunities for adolescent HIV prevention and diagnosis in a region of high HIV prevalence, we sought to describe pediatric emergency department (PED) visits made by a retrospective cohort of adolescents who were later diagnosed with HIV as young adults (<25 years) through an adult emergency department (ED) universal HIV screening program. CD4+ count was used to estimate the time of HIV infection before diagnosis and all PED visits in the 10 years before diagnosis were analyzed. Universal HIV screening in the adult ED diagnosed 193 young adults (median 22 years; 90% men; 29% stage 3); 70% had CD4+ at diagnosis that was used to estimate time of infection (mean 3.8 years). Thirty-eight HIV-infected young adults had a total of 109 PED visits in the 10 years before HIV diagnosis. Sexual history was documented in 12% of PED visits and a sexually transmitted infection test was sent in 6%. Ten HIV-infected young adults had 26 PED visits during the time in which they were likely already infected with HIV, each a potential missed opportunity for earlier diagnosis. HIV-infected and at-risk adolescents are underrecognized in PED visits. Implementation of CDC-recommended universal screening may lead to earlier diagnoses and improve outcomes; the PED may also be critical in identifying adolescents eligible for preexposure prophylaxis.

Objectives: to describe the first wave of the COVID-19 pandemic with a focus on undetected cases and to evaluate different post-lockdown scenarios., Design: the study introduces a SEIR compartmental model, taking into account the region-specific fraction of undetected cases, the effects of mobility restrictions, and the personal protective measures adopted, such as wearing a mask and washing hands frequently., Setting and Participants: the model is experimentally validated with data of all the Italian regions, some European countries, and the US., Main Outcome Measures: the accuracy of the model results is measured through the mean absolute percentage error (MAPE) and Lewis criteria; fitting parameters are in good agreement with previous literature., Results: the epidemic curves for different countries and the amount of undetected and asymptomatic cases are estimated, which are likely to represent the main source of infections in the near future. The model is applied to the Hubei case study, which is the first place to relax mobility restrictions. Results show different possible scenarios. Mobility and the adoption of personal protective measures greatly influence the dynamics of the infection, determining either a huge and rapid secondary epidemic peak or a more delayed and manageable one., Conclusions: mathematical models can provide useful insights for healthcare decision makers to determine the best strategy in case of future outbreaks.

SARS-CoV-2 started causing infections in humans in late 2019 and has spread rapidly around the world. While the number of symptomatically infected and severely ill people is high and has overwhelmed the medical systems of many countries, there is mounting evidence that some of the rapid spread of this virus has been driven by asymptomatic infections. In this study, we use a compartmental mathematical model of a viral epidemic that includes asymptomatic infection to examine the role of asymptomatic individuals in the spread of the infection. We apply the model to epidemics in California, Florida, New York, and Texas, finding that asymptomatic infections far outnumber reported symptomatic infections at the peak of the epidemic in all four states. The model suggests that relaxing of social distancing measures too quickly could lead to a rapid rise in the number of cases, driven in part by asymptomatic infections., Competing Interests: The authors have declared that no competing interests exist.

In the absence of an efficient drug treatment or a vaccine, the control of the COVID-19 pandemic relies on classic infection control measures. Since these means are socially disruptive and come with substantial economic loss for societies, a better knowledge of the epidemiology of the new coronavirus epidemic is crucial to achieve control at a sustainable cost and within tolerable restrictions of civil rights., (© 2020 Society for Applied Microbiology and John Wiley & Sons Ltd.)

Hepatitis E virus produces an emerging health problem, knowledge about epidemiology of hepatitis E virus infections in the USA and Latin America is still limited. The wide-ranging clinical manifestations lead to an extensive underestimation of the global seroprevalence. Clinical and diagnostic accuracy are critical to improve patient management., (Copyright © 2019 Fundación Clínica Médica Sur, A.C. Published by Elsevier España, S.L.U. All rights reserved.)

Background: Prevention of bacterial sexually transmitted infections (STIs) among men who have sex with men (MSM) requires timely disease detection, but this is complicated by asymptomatic infection. We estimated screening/testing rates by symptomatic status to evaluate adherence to Centers for Disease Control and Prevention STI screening guidelines., Methods: In a cross-sectional study of 2572 US MSM aged 15 to 65 years in 2017 to 2018, we measured the reported number of asymptomatic STI screens in the past 2 years versus tests prompted by disease symptoms. Using negative binominal regression within a hierarchical Bayesian framework, we estimated yearly rates of asymptomatic screening and symptomatic testing by geographic, demographic, and behavioral factors., Results: Human immunodeficiency virus (HIV) status was most strongly associated with all testing/screening frequency (incidence rate ratio [IRR], 1.72; 95% credible interval [Crl], 1.49, 1.97). The HIV-uninfected MSM had 0.14 (95% credible interval [CrI], 0.12-0.17) symptomatic tests and 0.88 (95% CrI, 0.77-1.01) asymptomatic screens per year. The HIV-infected MSM had 0.25 (95% CrI, 0.18-0.35) symptomatic tests and 1.53 (95% CrI, 1.24-1.88) asymptomatic screens per year. Rates of asymptomatic screening were higher among black compared with white MSM (IRR, 1.41; 95% CrI, 1.15-1.73), but weakly associated with number of past-year sexual partners (IRR, 1.01; 95% CrI, 1.00-1.01). Overall, 85% to 90% of diagnostic events were asymptomatic screens., Conclusions: Self-reported rates of STI screening were close to Centers for Disease Control and Prevention's recommended overall annual screening frequency, but with gaps defined by demographics and behavioral risk. Targeted screening efforts may be indicated specifically for younger MSM and those with multiple partners.

Background: Mycoplasma genitalium can result in pelvic inflammatory disease and adverse pregnancy outcomes. We analyzed data collected from a prospective study of asymptomatic bacterial vaginosis (BV) to determine the natural history of M. genitalium., Methods: Women aged 15-25 years, with asymptomatic BV and ≥2 risk factors for sexually transmitted infection were recruited from 10 sites throughout the United States. Vaginal swab samples were collected at enrollment and through home-based testing every 2 months over 12 months. M. genitalium nucleic acid amplification testing was performed for M. genitalium using transcription-mediated assays (Hologic). The prevalence, incidence, and persistence of M. genitalium, defined as all positive specimens during follow-up, were estimated with 95% confidence intervals (CIs). Adjusted odds ratios (AOR) were calculated using logistic and Poisson regression to evaluate participant characteristics associated with M. genitalium infection., Results: Among 1139 women, 233 were M. genitalium positive, for a prevalence of 20.5% (95% CI, 18.2%-22.9%); 42 of 204 had persistent M. genitalium (20.6%). Among 801 M. genitalium-negative women at baseline, the M. genitalium incidence was 36.6 per 100 person-years (95% CI, 32.4-41.3). Black race (AOR, 1.92; 95% CI, 1.09-3.38), age ≤21 years (1.40; 1.03-1.91), and prior pregnancy (1.36; 1.00-1.85) were associated with prevalent M. genitalium; only black race was associated with incident M. genitalium (P = .03)., Conclusions: We identified high rates of prevalent, incident, and persistent M. genitalium infections among young, high-risk women with asymptomatic BV, supporting the need for clinical trials to evaluate the impact of M. genitalium screening on female reproductive health outcomes.

Importance: In 2014, 19,999 cases of syphilis were reported in the United States. Left untreated, syphilis can progress to late-stage disease in about 15% of persons who are infected. Late-stage syphilis can lead to development of inflammatory lesions throughout the body, which can lead to cardiovascular or organ dysfunction. Syphilis infection also increases the risk for acquiring or transmitting HIV infection., Objective: To update the 2004 US Preventive Services Task Force (USPSTF) recommendation on screening for syphilis infection in nonpregnant adults. Screening for syphilis in pregnant women was updated in a separate recommendation statement in 2009 (A recommendation)., Evidence Review: The USPSTF reviewed the evidence on screening for syphilis infection in asymptomatic, nonpregnant adults and adolescents, including patients coinfected with other sexually transmitted infections (such as HIV)., Findings: The USPSTF found convincing evidence that screening for syphilis infection in asymptomatic, nonpregnant persons at increased risk for infection provides substantial benefit. Accurate screening tests are available to identify syphilis infection in populations at increased risk. Effective treatment with antibiotics can prevent progression to late-stage disease, with small associated harms, providing an overall substantial health benefit., Conclusions and Recommendation: The USPSTF recommends screening for syphilis infection in persons who are at increased risk for infection. (A recommendation).

Trichomonas vaginalis is the most prevalent nonviral sexually transmitted infection, affecting an estimated 3.7 million women and men in the United States. Health disparities are prominent in the epidemiology of this infection, which affects 11% of women aged ≥40 years and a disproportionately high percentage of black women. Particularly high prevalences have been identified among sexually transmitted disease (STD) clinic patients and incarcerated individuals. This article reviews and updates scientific evidence in key topic areas used for the development of the 2015 STD Treatment Guidelines published by the Centers for Disease Control and Prevention. Current evidence is presented regarding conditions associated with Trichomonas vaginalis infection, including human immunodeficiency virus (HIV) and pregnancy complications such as preterm birth. Nucleic acid amplification tests and point-of-care tests are newly available diagnostic methods that can be conducted on a variety of specimens, potentially allowing highly sensitive testing and screening of both women and men at risk for infection. Usually, trichomoniasis can be cured with single-dose therapy of an appropriate nitroimidazole antibiotic, but women who are also infected with HIV should receive therapy for 7 days. Antimicrobial resistance is an emerging concern., (Published by Oxford University Press for the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

We screened 52 children adopted from Ethiopia for malaria because they had previously lived in a disease-endemic region or had past or current hepatomegaly or splenomegaly. Seven (13.5%) children had asymptomatic malaria parasitemia by microscopy (n = 2) or PCR (n = 5). Our findings suggest that adoptees at risk for asymptomatic malaria should be screened, preferably by PCR.

Salmonella enterica commonly colonizes the intestinal tract of cattle and is a leading cause of foodborne illness. A previously described investigation into the prevalence of S. enterica on a dairy farm revealed an 8-year-long asymptomatic S. enterica epidemic caused by serotypes Cerro and Kentucky in the lactating herd. To investigate the source of the S. Kentucky strains, the genomes of two S. Kentucky isolates were sequenced; one collected prior to the epidemic (2004) and one collected during the epidemic (2010). Comparative genomic analysis demonstrated significant polymorphisms between the two strains. PCR primers targeting unique and strain-specific regions were developed, and screening of the archived isolates identified the index case of the asymptomatic S. Kentucky epidemic as a heifer that was raised off-site and transported onto the study farm in 2005. Analysis of isolates collected from all heifers brought onto the farm demonstrated frequent re-introduction of clones of the epidemic strain suggesting transmission of pathogens between farms might occur repeatedly.

Urinary tract infection (UTI) is common in long-term care (LTC) residents; however, most infections are asymptomatic and do not require treatment. Differentiating asymptomatic from symptomatic UTI is challenging, because LTC residents typically have chronic genitourinary complaints, multiple comorbid illnesses, and communication barriers. Although consensus guidelines have been proposed to improve the accuracy of identifying symptomatic UTIs and minimize treatment of asymptomatic UTIs, diagnostic accuracy is not yet optimized. Strategies for prevention of UTI are unsatisfactory and require further study; nevertheless, there is some evidence for the efficacy of cranberry products and vaginal estrogen to prevent recurrent UTI in women., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Background: Without diagnosis and antiviral therapy, many patients with chronic hepatitis C infections will develop end-stage liver disease and die from complications., Aims: To evaluate the future impacts of preventive interventions and treatment advances, this paper forecasts a baseline estimate of the future morbidity and mortality of prevalent hepatitis C when left untreated., Methods: We simulated the future disease progression and death for all Americans with prevalent hepatitis C in 2005. To validate the model, we used past seroprevalence to forecast contemporary outcomes. We used the validated model to forecast future cases of end-stage liver disease, transplants, and deaths from 2010 to 2060, and we estimated credible intervals using Monte Carlo simulation., Results: When programmed with past data, our model predicted current levels of hepatitis C outcomes with accuracy between ±1% and 13%. Morbidity and mortality from hepatitis C will rise from 2010 to a peak between the years 2030 and 2035. We forecasted a peak of 38,600 incident cases of end-stage liver disease; 3200 referrals for transplant; and 36,100 deaths., Conclusions: Because current rates of screening and treatment are low, future morbidity and mortality from hepatitis C are likely to increase substantially without public health interventions to increase treatment., (Copyright © 2010 Editrice Gastroenterologica Italiana S.r.l. All rights reserved.)

Aim: This article is a report of a study of the use of predictive analysis using the Bayesian hierarchical model and small area estimation as an innovative methodology to address the challenges nurses face when managing fiscal and clinical resources in outpatient and inpatient settings., Background: Nurses responsible for clinic management are confronted with the fiscal challenges in today's healthcare environment. Identifying those at risk for asymptomatic infections such as chlamydia and getting resources to that group has been a constant nursing care challenge for those in outpatient and inpatient clinics., Methods: A secondary analysis of quantitative survey data was conducted in 2008, using predictive analysis with the Bayesian hierarchical model and small area estimation of statistics., Discussion: The development of an innovative statistical procedure is an interesting and challenging opportunity. The opportunity to apply this innovative technique to an actual data set opens the possibility to replicating the technique and using it in other settings. If implemented and replicated, this innovative analysis can become a tool for managing limited fiscal and clinical resources., Results: White, Hispanic and African American undergraduate students had slightly higher rates than the corresponding graduate students. The incidence rates were higher for White, Hispanic and African American undergraduate students than for graduate students. The incidence rates for African Americans were much higher than for the other identified racial groups, but very similar for graduate students and undergraduate students., Conclusion: Predictive analysis using the Bayesian hierarchal model and small area estimation can help nurses to project healthcare costs and services for underserved groups in healthcare clinics, with an improved empirical rationale., (© 2010 Blackwell Publishing Ltd.)