Objective To determine whether modified K–12 student quarantine policies that allow some students to continue in-person education during their quarantine period increase schoolwide SARS-CoV-2 transmission risk following the increase in cases in winter 2020–2021. Methods We conducted a prospective cohort study of COVID-19 cases and close contacts among students and staff (n = 65,621) in 103 Missouri public schools. Participants were offered free, saliva-based RT-PCR testing. The projected number of school-based transmission events among untested close contacts was extrapolated from the percentage of events detected among tested asymptomatic close contacts and summed with the number of detected events for a projected total. An adjusted Cox regression model compared hazard rates of school-based SARS-CoV-2 infections between schools with a modified versus standard quarantine policy. Results From January–March 2021, a projected 23 (1%) school-based transmission events occurred among 1,636 school close contacts. There was no difference in the adjusted hazard rates of school-based SARS-CoV-2 infections between schools with a modified versus standard quarantine policy (hazard ratio = 1.00; 95% confidence interval: 0.97–1.03). Discussion School-based SARS-CoV-2 transmission was rare in 103 K–12 schools implementing multiple COVID-19 prevention strategies. Modified student quarantine policies were not associated with increased school incidence of COVID-19. Modifications to student quarantine policies may be a useful strategy for K–12 schools to safely reduce disruptions to in-person education during times of increased COVID-19 community incidence.

Background Since March 2020, COVID-19 has disproportionately impacted communities of color within the United States. As schools have shifted from virtual to in-person learning, continual guidance is necessary to understand appropriate interventions to prevent SARS-CoV-2 transmission. Weekly testing of students and staff for SARS-CoV-2 within K-12 school setting could provide an additional barrier to school-based transmission, especially within schools unable to implement additional mitigation strategies and/or are in areas of high transmission. This study seeks to understand the role that weekly SARS-CoV-2 testing could play in K-12 schools. In addition, through qualitative interviews and listening sessions, this research hopes to understand community concerns and barriers regarding COVID-19 testing, COVID-19 vaccine, and return to school during the COVID-19 pandemic. Methods/design Sixteen middle and high schools from five school districts have been randomized into one of the following categories: (1) Weekly screening + symptomatic testing or (2) Symptomatic testing only. The primary outcome for this study will be the average of the secondary attack rate of school-based transmission per case. School-based transmission will also be assessed through qualitative contact interviews with positive contacts identified by the school contact tracers. Lastly, new total numbers of weekly cases and contacts within a school-based quarantine will provide guidance on transmission rates. Qualitative focus groups and interviews have been conducted to provide additional understanding to the acceptance of the intervention and barriers faced by the community regarding SARS-CoV-2 testing and vaccination. Discussion This study will provide greater understanding of the benefit that weekly screening testing can provide in reducing SARS-CoV-2 transmission within K-12 schools. Close collaboration with community partners and school districts will be necessary for the success of this and similar studies. Trial Registration NCT04875520. Registered May 6, 2021.

ObjectiveTo determine whether modified K–12 student quarantine policies that allow some students to continue in-person education during their quarantine period increase schoolwide SARS-CoV-2 transmission risk following the increase in cases in winter 2020-2021.MethodsWe conducted a prospective cohort study of COVID-19 cases and exposures among students and staff (n=65,621) in 103 Missouri public schools. Participants were offered free, saliva-based RT-PCR testing. An adjusted Cox regression model compared hazard rates of school-based SARS-CoV-2 infections between schools with a modified versus standard quarantine policy.ResultsFrom January–March 2021, a projected 23 (1%) school-based transmission events occurred among 1,636 school close contacts. There was no difference in the adjusted hazard rates of school-based SARS-CoV-2 infections between schools with a modified versus standard quarantine policy (hazard ratio=1.00; 95% confidence interval: 0.97–1.03).DiscussionSchool-based SARS-CoV-2 transmission was rare in 103 K–12 schools implementing multiple COVID-19 prevention strategies. Modified student quarantine policies were not associated with increased school incidence of COVID-19. Modifications to student quarantine policies may be a useful strategy for K–12 schools to safely reduce disruptions to in-person education during times of increased COVID-19 community incidence.

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Background Case and contact investigation is a mitigation strategy to understand transmission of diseases. The goal of this study is to assess COVID-19 transmission in schools that employ contact tracing. Methods Five middle and high schools provided a list of ongoing student and staff cases and their school contacts for the 2021-22 school year. Cases were eligible for interview if they had a known positive test or were a “presumed positive” by a practitioner. Contacts were eligible if they were identified as a close contact to a case within their school. Contacts who later became a case were eligible for a separate case interview. Trained interviewers contacted eligible individuals to offer COVID-19 resources and determine interests in participating in the study. Interested cases and contacts underwent a semi-structured interview with standardized questions. Results From 5/2021-4/2022, 360 cases (45% during Omicron surge) and their 412 contacts were identified (Fig 1). Among the 111 cases interviewed, 75% were students, half were in grades 6-8 (Fig 2). 61% of the cases were vaccinated with their primary series. 92% were symptomatic and fatigue, cough, and headaches were the most common symptoms. Transmission from school occurred in 29% (Fig 3) and most commonly occurred in the classroom. Among the 68 contacts interviewed, 96% were students. The two most reported activities contacts participated in were band (n=9) and sports (n=22), 10 from playing basketball. Three contacts reported exposure to COVID-19 within the household and five contacts reported exposure outside the home or school. Conclusion Case and contact investigation can be a valuable tool to assess COVID-19 transmission in schools. Almost one-third of cases reported school exposures, a greater school transmission rate than previous reported likely do to the increased transmissibility of Omicron. Assessing transmission events with this strategy alone may be limited by its reliance on self-reports. Case investigations can help schools identify potential areas to improve in limiting school-based COVID-19 transmission. Disclosures Sara Malone, PhD, LCSW, AHRQ: Grant/Research Support|NIH: Grant/Research Support Jason Newland, MD, AHRQ: Grant/Research Support|Merck: Grant/Research Support|NIH: Grant/Research Support|PEW Charitable Trust: Grant/Research Support|Pfizer: Grant/Research Support.