{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,7,30]],"date-time":"2025-07-30T16:30:44Z","timestamp":1753893044025,"version":"3.41.2"},"reference-count":38,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,6,12]],"date-time":"2025-06-12T00:00:00Z","timestamp":1749686400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Public Health"],"abstract":"Background<\/jats:title>School masking mandates were widely adopted as a pandemic control measure, however, limited data are available regarding their effectiveness as a strategy for reducing burden of disease in the surrounding community.<\/jats:p><\/jats:sec>Objective<\/jats:title>To evaluate the impact of school masking policy de-adoption (mask-lifting) on SARS-CoV-2 incidence rates, hospitalizations, and deaths in the surrounding community.<\/jats:p><\/jats:sec>Methods<\/jats:title>Design<\/jats:italic>: Retrospective observational study with an event study design, a difference-in-difference method; a target trial emulation (TTE) framework was applied as a secondary analysis. Cohort creation<\/jats:italic>: Data collected from 9\/2021 to 6\/2022 on SARS-CoV-2 cases, hospitalizations, deaths and vaccination rates were combined with district-level masking policy data. Analysis<\/jats:italic>: In the event study, the impact of masking policy de-adoption on SARS-CoV-2 cases per 100,000 county residents stratified by age during the 8-week period following the policy change was estimated. Effects on hospitalization and deaths per 1,000,000 residents were secondarily estimated. In a secondary analysis, a target trial emulation framework was applied to estimate average treatment effects.<\/jats:p><\/jats:sec>Results<\/jats:title>N<\/jats:italic>\u202f=\u202f3,970 districts composed of 53,453 schools were included in the cohort. In the event study, no consistent trends for COVID-19 case rates were identified for the whole cohort or for any age group. For the whole cohort, there was a statistically significant increase found 6\u20138\u202fweeks following the policy change (maximum increase, 1.91 hospitalizations per 1,000,000 county residents); increases in hospitalizations were also found in the stratified analysis for all age groups, although absolute impacts were small. An increase in deaths was found during the period from 4 to 7\u202fweeks following the policy change (maximum increase 0.62 deaths per 1,000,000 residents). In the stratified analysis, small increases in death rates were seen in 50\u201369\u202fyear olds (range, 0.088\u20131.49) and &gt;70\u202fyear olds (range, 0.23\u20132.58) but not in younger groups. In the TTE framework, cases, hospitalizations, and deaths were similar in control and intervention counties.<\/jats:p><\/jats:sec>Conclusion<\/jats:title>This study evaluating the impact of lifting of mask mandates in schools, analyzed in two ways, was consistent results ranging from no impact to a small but statistically significant impact of the policy change on SARS-CoV-2 case and severe outcomes rates in the surrounding community. Findings can be used to inform future pandemic policy responses for elementary and secondary schools.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fpubh.2025.1579202","type":"journal-article","created":{"date-parts":[[2025,6,12]],"date-time":"2025-06-12T05:21:34Z","timestamp":1749705694000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Impact of lifting school mask mandates on community SARS-CoV-2 cases, hospitalizations, and deaths: a retrospective observational study"],"prefix":"10.3389","volume":"13","author":[{"given":"Zeynep","family":"Ertem","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Anseh","family":"Danesharasteh","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sonia T.","family":"Anand","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nicholas J.","family":"Jackson","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Richard E.","family":"Nelson","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Elissa M.","family":"Schechter-Perkins","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lloyd","family":"Fisher","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shira","family":"Doron","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Westyn","family":"Branch-Elliman","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2025,6,12]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"10","DOI":"10.1016\/j.epidem.2015.04.003","article-title":"On the relative role of different age groups in influenza epidemics","volume":"13","author":"Worby","year":"2015","journal-title":"Epidemics"},{"key":"ref2","doi-asserted-by":"publisher","first-page":"e82","DOI":"10.1017\/ash.2023.154","article-title":"The next \u2018pandemic playbook\u2019 needs to prioritize the needs of children\u2014and a clear roadmap for opening schools","volume":"3","author":"Branch-Elliman","year":"2023","journal-title":"Antimicrob Stewardsh Healthc Epidemiol"},{"key":"ref3","doi-asserted-by":"publisher","first-page":"2500","DOI":"10.3390\/ijerph19052500","article-title":"Do the benefits of school closure outweigh its costs?","volume":"19","author":"Raffetti","year":"2022","journal-title":"Int J Environ Res Public Health"},{"key":"ref4","doi-asserted-by":"publisher","first-page":"750","DOI":"10.1038\/nature06732","article-title":"Estimating the impact of school closure on influenza transmission from sentinel data","volume":"452","author":"Cauchemez","year":"2008","journal-title":"Nature"},{"key":"ref5","first-page":"ofab134","article-title":"The science behind safe school re-opening: leveraging the pillars of infection control to support safe elementary and secondary education during the COVID-19 pandemic","volume-title":"Open forum infectious diseases","author":"Schechter-Perkins","year":"2022"},{"key":"ref6","article-title":"Education Week Staff. Forever changed: a timeline of how COVID upended schools","author":"Baker","year":"2022","journal-title":"Educ Week"},{"volume-title":"Timeline: changes to CDC mask guidelines since the pandemic began","year":"2021","author":"Cohan","key":"ref7"},{"key":"ref8","doi-asserted-by":"crossref","first-page":"203","DOI":"10.1093\/cid\/ciad115","article-title":"Condition-dependent and dynamic impacts of indoor masking policies for Coronavirus disease 2019 mitigation: a nationwide, interrupted time-series analysis","volume":"77","author":"Ertem","year":"2023","journal-title":"Clin Infect Dis"},{"key":"ref9","doi-asserted-by":"publisher","first-page":"eabi9069","DOI":"10.1126\/science.abi9069","article-title":"Impact of community masking on COVID-19: a cluster-randomized trial in Bangladesh","volume":"375","author":"Abaluck","year":"2022","journal-title":"Science"},{"key":"ref10","doi-asserted-by":"publisher","first-page":"335","DOI":"10.7326\/M20-6817","article-title":"Effectiveness of adding a mask recommendation to other public health measures to prevent SARS-CoV-2 infection in Danish mask wearers: a randomized controlled trial","volume":"174","author":"Bundgaard","year":"2021","journal-title":"Ann Intern Med"},{"key":"ref11","doi-asserted-by":"publisher","first-page":"1935","DOI":"10.1056\/NEJMoa2211029","article-title":"Lifting universal masking in schools\u2014COVID-19 incidence among students and staff","volume":"387","author":"Cowger","year":"2022","journal-title":"N Engl J Med"},{"key":"ref12","doi-asserted-by":"publisher","first-page":"131","DOI":"10.1136\/archdischild-2022-324172","article-title":"Unravelling the role of the mandatory use of face covering masks for the control of SARS-CoV-2 in schools: a quasi-experimental study nested in a population-based cohort in Catalonia (Spain)","volume":"108","author":"Coma","year":"2023","journal-title":"Arch Dis Child"},{"volume-title":"Risk for COVID-19 infection, hospitalization, and death by age group","year":"2021","key":"ref13"},{"key":"ref14","doi-asserted-by":"publisher","first-page":"e2103420118","DOI":"10.1073\/pnas.2103420118","article-title":"The association of opening K\u201312 schools with the spread of COVID-19 in the United States: county-level panel data analysis","volume":"118","author":"Chernozhukov","year":"2021","journal-title":"Proc Natl Acad Sci"},{"key":"ref15","doi-asserted-by":"publisher","first-page":"397","DOI":"10.1016\/S2352-4642(20)30095-X","article-title":"School closure and management practices during coronavirus outbreaks including COVID-19: a rapid systematic review","volume":"4","author":"Viner","year":"2020","journal-title":"Lancet Child Adolesc Health"},{"key":"ref16","doi-asserted-by":"publisher","first-page":"2446","DOI":"10.1001\/jama.2022.21383","article-title":"Target trial emulation: a framework for causal inference from observational data","volume":"328","author":"Hern\u00e1n","year":"2022","journal-title":"JAMA"},{"key":"ref17","doi-asserted-by":"publisher","first-page":"758","DOI":"10.1093\/aje\/kwv254","article-title":"Using big data to emulate a target trial when a randomized trial is not available","volume":"183","author":"Hern\u00e1n","year":"2016","journal-title":"Am J Epidemiol"},{"year":"2023","key":"ref18"},{"year":"2023","key":"ref19"},{"volume-title":"Educational technology in teacher education programs for initial licensure. Statistical analysis report.","year":"2007","author":"Kleiner","key":"ref20"},{"volume-title":"Google COVID-19 community mobility reports","year":"2022","key":"ref21"},{"year":"2023","key":"ref22"},{"year":"2024","author":"Now","key":"ref23"},{"key":"ref24","doi-asserted-by":"publisher","first-page":"853","DOI":"10.1177\/1536867X211063144","article-title":"Implementing the panel event study","volume":"21","author":"Clarke","year":"2021","journal-title":"Stata J"},{"volume-title":"School districts and associated counties","year":"2022","author":"Bureau","key":"ref25"},{"key":"ref26","doi-asserted-by":"publisher","first-page":"e2240037","DOI":"10.1001\/jamanetworkopen.2022.40037","article-title":"Factors associated with severe COVID-19 among vaccinated adults treated in US veterans affairs hospitals","volume":"5","author":"Vo","year":"2022","journal-title":"JAMA Netw Open"},{"key":"ref27","doi-asserted-by":"publisher","first-page":"1566","DOI":"10.7326\/M23-2907","article-title":"School mask mandates and COVID-19: the challenge of using difference-in-differences analysis of observational data to estimate the effectiveness of a public health intervention","volume":"177","author":"Chandra","year":"2024","journal-title":"Ann Intern Med"},{"key":"ref28","doi-asserted-by":"publisher","first-page":"849","DOI":"10.7326\/M23-0618","article-title":"Improving COVID-19 disease severity surveillance measures: statewide implementation experience","volume":"176","author":"Doron","year":"2023","journal-title":"Ann Intern Med"},{"key":"ref29","doi-asserted-by":"publisher","first-page":"1314","DOI":"10.1056\/NEJMoa2119658","article-title":"Population immunity and COVID-19 severity with Omicron variant in South Africa","volume":"386","author":"Madhi","year":"2022","journal-title":"N Engl J Med"},{"key":"ref30","doi-asserted-by":"publisher","first-page":"1419","DOI":"10.1016\/S1473-3099(22)00547-3","article-title":"Uncoupling of all-cause excess mortality from COVID-19 cases in a highly vaccinated state","volume":"22","author":"Faust","year":"2022","journal-title":"Lancet Infect Dis"},{"key":"ref31","doi-asserted-by":"publisher","first-page":"e0285009","DOI":"10.1371\/journal.pone.0285009","article-title":"Acoustic and perceptual impact of face masks on speech: a scoping review","volume":"18","author":"Badh","year":"2023","journal-title":"PLoS One"},{"key":"ref32","doi-asserted-by":"publisher","first-page":"14848","DOI":"10.1038\/s41598-023-40007-w","article-title":"Influence of child and adult faces with face masks on emotion perception and facial mimicry","volume":"13","author":"Kastendieck","year":"2023","journal-title":"Sci Rep"},{"key":"ref33","doi-asserted-by":"publisher","first-page":"815259","DOI":"10.3389\/fpubh.2022.815259","article-title":"Impact of SARS-CoV-2 virus (COVID-19) preventative measures on communication: a scoping review","volume":"10","author":"Oosthuizen","year":"2022","journal-title":"Front Public Health"},{"key":"ref34","doi-asserted-by":"publisher","first-page":"1247","DOI":"10.1093\/cid\/ciad381","article-title":"Maintaining the utility of COVID-19 pandemic severity surveillance: evaluation of trends in attributable deaths and development and validation of a measurement tool","volume":"77","author":"Trottier","year":"2023","journal-title":"Clin Infect Dis"},{"key":"ref35","doi-asserted-by":"publisher","first-page":"149","DOI":"10.1017\/ice.2022.79","article-title":"Coronavirus disease 2019 (COVID-19) hospitalization metrics that do not account for disease severity underestimate protection provided by severe acute respiratory coronavirus virus 2 (SARS-CoV-2) vaccination and boosting: a retrospective cohort study","volume":"44","author":"Corrigan","year":"2023","journal-title":"Infect Control Hosp Epidemiol"},{"key":"ref36","doi-asserted-by":"publisher","first-page":"1767","DOI":"10.1017\/ice.2022.13","article-title":"The COVID-19 hospitalization metric in the pre-and postvaccination eras as a measure of pandemic severity: a retrospective, nationwide cohort study","volume":"43","author":"Fillmore","year":"2022","journal-title":"Infect Control Hosp Epidemiol"},{"key":"ref37","doi-asserted-by":"publisher","first-page":"315","DOI":"10.1097\/INF.0000000000003823","article-title":"Incidence rates of medically attended COVID-19 in infants less than 6 months of age","volume":"42","author":"Griffin","year":"2022","journal-title":"Pediatr Infect Dis J"},{"key":"ref38","doi-asserted-by":"publisher","first-page":"202","DOI":"10.1038\/s43856-024-00619-3","article-title":"Impacts of testing and immunity acquired through vaccination and infection on covid-19 cases in Massachusetts elementary and secondary students","volume":"4","author":"Branch-Elliman","year":"2024","journal-title":"Commun Med"}],"container-title":["Frontiers in Public Health"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fpubh.2025.1579202\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,6,12]],"date-time":"2025-06-12T05:21:36Z","timestamp":1749705696000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fpubh.2025.1579202\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,6,12]]},"references-count":38,"alternative-id":["10.3389\/fpubh.2025.1579202"],"URL":"https:\/\/doi.org\/10.3389\/fpubh.2025.1579202","relation":{},"ISSN":["2296-2565"],"issn-type":[{"type":"electronic","value":"2296-2565"}],"subject":[],"published":{"date-parts":[[2025,6,12]]},"article-number":"1579202"}}