{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,17]],"date-time":"2026-10-17T04:55:28Z","timestamp":1792212928288,"version":"4.4.0"},"reference-count":34,"publisher":"American Medical Association (AMA)","issue":"10","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JAMA Netw Open"],"abstract":"Importance<\/jats:title>The magnitude of school respiratory virus exposure and the effectiveness of environmental mitigation measures remain unclear.<\/jats:p><\/jats:sec>Objective<\/jats:title>To evaluate whether portable high-efficiency particulate air (HEPA) purifiers are associated with reduced respiratory virus exposure in elementary school classrooms.<\/jats:p><\/jats:sec>Design, Setting, and Participants<\/jats:title>This ad hoc secondary analysis was performed between July 2023 and September 2024 and used data from a cluster-randomized, placebo-controlled trial (School Inner-City Asthma Intervention Study) of HEPA purifiers conducted from September 2015 to June 2020. A total of 200 classrooms from 39 public schools in Northeastern US were enrolled and randomized.<\/jats:p><\/jats:sec>Interventions<\/jats:title>Classrooms were randomized 1:1 to receive either active HEPA purifiers or visually identical sham HEPA units (4 per classroom). School staff and investigators were blinded to intervention assignments.<\/jats:p><\/jats:sec>Main Outcomes and Measures<\/jats:title>The primary outcome was high viral exposure, identified by K-means clustering of individual viral concentrations. Secondary outcomes included viral diversity (defined as number of detected virus types) and individual viral concentrations. Week-long bioaerosol samples were collected 3 times during 1 school year, and concentrations of 19 respiratory viruses were quantified by digital droplet polymerase chain reaction.<\/jats:p><\/jats:sec>Results<\/jats:title>Of the 200 enrolled classrooms (91 in the sham purifier group and 109 in the HEPA purifier group) analyzed, the median (IQR) class size was 19 (18-20) and the median (IQR) grade was 3 (2-5). A total of 532 bioaerosol samples were collected; viruses were detected in 524 samples (98.5%), with a median (IQR) of 3 (2-5) viruses per classroom. Rhinovirus was most prevalent (476 [89.5%]), while respiratory syncytial virus A and B (66 [12.4%] and 127 [23.9%]) as well as influenza A and B (94 [17.7%] and 76 [14.3%]) were also detected. High viral exposure was present in 118 samples (22.2%). The HEPA purifier intervention was not associated with lower odds of high viral exposure (odds ratio [OR], 0.50; 95% CI, 0.08-3.25; P<\/jats:italic>\u2009=\u2009.46) but did correspond to a modest reduction in viral diversity (\u03b2\u2009=\u2009\u22121.02; 95% CI, \u20131.68 to \u22120.35; P<\/jats:italic>\u2009=\u2009.003). Elastic net regression identified relative humidity, grade, winter season, and coarse particulate matter as the environmental risk factors for viral exposure.<\/jats:p><\/jats:sec>Conclusions and Relevance<\/jats:title>In this secondary analysis, HEPA purifiers were not associated with a reduction in high viral exposure but were associated with a modest decrease in viral diversity. Multicomponent interventions may be needed to mitigate respiratory viral exposures in schools.<\/jats:p><\/jats:sec>","DOI":"10.1001\/jamanetworkopen.2025.36951","type":"journal-article","created":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T15:30:40Z","timestamp":1760110240000},"page":"e2536951","source":"Crossref","is-referenced-by-count":10,"title":["Air Purifier Intervention for Respiratory Viral Exposure in Elementary Schools"],"prefix":"10.1001","volume":"8","author":[{"given":"Ye","family":"Sun","sequence":"first","affiliation":[{"name":"Division of Pulmonary Medicine, Boston Children\u2019s Hospital, Boston, Massachusetts"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dastan","family":"Haghnazari","sequence":"additional","affiliation":[{"name":"Division of Pulmonary and Critical Care, Massachusetts General Hospital, Boston"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ching-Ying","family":"Huang","sequence":"additional","affiliation":[{"name":"Division of Pulmonary and Critical Care, Massachusetts General Hospital, Boston"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aribah","family":"Baig","sequence":"additional","affiliation":[{"name":"Division of Pulmonary and Critical Care, Massachusetts General Hospital, Boston"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Minsik","family":"Kim","sequence":"additional","affiliation":[{"name":"Division of Pulmonary and Critical Care, Massachusetts General Hospital, Boston"},{"name":"Department of Biological Engineering, Inha University, Incheon, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Amparito","family":"Cunningham","sequence":"additional","affiliation":[{"name":"Division of Allergy and Immunology, Boston Children\u2019s Hospital, Boston, Massachusetts"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Colin","family":"Skeen","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering, Boston University, Boston, Massachusetts"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jack M.","family":"Wolfson","sequence":"additional","affiliation":[{"name":"Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stephen T.","family":"Ferguson","sequence":"additional","affiliation":[{"name":"Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Erica D.","family":"Pratt","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering, Boston University, Boston, Massachusetts"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Linda","family":"Valeri","sequence":"additional","affiliation":[{"name":"Department of Biostatistics, Columbia Mailman School of Public Health, New York, New York"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sophia","family":"Zhao","sequence":"additional","affiliation":[{"name":"Division of Pulmonary and Critical Care, Massachusetts General Hospital, Boston"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Diane R.","family":"Gold","sequence":"additional","affiliation":[{"name":"Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts"},{"name":"Channing Division of Network Medicine, Brigham and Women\u2019s Hospital, Boston, Massachusetts"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Leonora","family":"Balaj","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Massachusetts General Hospital, Boston"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Petros","family":"Koutrakis","sequence":"additional","affiliation":[{"name":"Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wanda","family":"Phipatanakul","sequence":"additional","affiliation":[{"name":"Division of Allergy and Immunology, Boston Children\u2019s Hospital, Boston, Massachusetts"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peggy S.","family":"Lai","sequence":"additional","affiliation":[{"name":"Division of Pulmonary and Critical Care, Massachusetts General Hospital, Boston"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"10","published-online":{"date-parts":[[2025,10,10]]},"reference":[{"issue":"9725","key":"zoi251022r1","doi-asserted-by":"publisher","first-page":"1545","DOI":"10.1016\/S0140-6736(10)60206-1","article-title":"Global burden of acute lower respiratory infections due to respiratory syncytial virus in young children: a systematic review and meta-analysis.","volume":"375","author":"Nair","year":"2010","journal-title":"Lancet"},{"issue":"1","key":"zoi251022r2","doi-asserted-by":"publisher","first-page":"47","DOI":"10.1016\/j.yapd.2009.08.019","article-title":"Severe childhood respiratory viral infections.","volume":"56","author":"Hon","year":"2009","journal-title":"Adv Pediatr"},{"issue":"3","key":"zoi251022r3","doi-asserted-by":"publisher","first-page":"220","DOI":"10.1111\/irv.12440","article-title":"School absenteeism among school-aged children with medically attended acute viral respiratory illness during three influenza seasons, 2012-2013 through 2014-2015.","volume":"11","author":"McLean","year":"2017","journal-title":"Influenza Other Respir Viruses"},{"issue":"4","key":"zoi251022r4","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0267111","article-title":"Cause-specific student absenteeism monitoring in K-12 schools for detection of increased influenza activity in the surrounding community-Dane County, Wisconsin, 2014-2020.","volume":"17","author":"Temte","year":"2022","journal-title":"PLoS One"},{"issue":"6","key":"zoi251022r5","doi-asserted-by":"publisher","first-page":"877","DOI":"10.1086\/655810","article-title":"School opening dates predict pandemic influenza A(H1N1) outbreaks in the United States.","volume":"202","author":"Chao","year":"2010","journal-title":"J Infect Dis"},{"issue":"35","key":"zoi251022r6","doi-asserted-by":"publisher","first-page":"1214","DOI":"10.15585\/mmwr.mm7035e2","article-title":"Outbreak associated with SARS-CoV-2 B.1.617.2 (Delta) variant in an elementary school\u2014Marin County, California, May-June 2021.","volume":"70","author":"Lam-Hine","year":"2021","journal-title":"MMWR Morb Mortal Wkly Rep"},{"issue":"5","key":"zoi251022r7","doi-asserted-by":"publisher","first-page":"850","DOI":"10.1093\/cid\/ciz296","article-title":"Detection of influenza and other respiratory viruses in air sampled from a university campus: a longitudinal study.","volume":"70","author":"Xie","year":"2020","journal-title":"Clin Infect Dis"},{"issue":"1","key":"zoi251022r8","doi-asserted-by":"publisher","first-page":"4717","DOI":"10.1038\/s41467-022-32406-w","article-title":"SARS-CoV-2 and other respiratory pathogens are detected in continuous air samples from congregate settings.","volume":"13","author":"Ramuta","year":"2022","journal-title":"Nat Commun"},{"issue":"12","key":"zoi251022r9","doi-asserted-by":"publisher","DOI":"10.1001\/jamanetworkopen.2023.46329","article-title":"Four methods for monitoring SARS-CoV-2 and influenza A virus activity in schools.","volume":"6","author":"Temte","year":"2023","journal-title":"JAMA Netw Open"},{"issue":"4","key":"zoi251022r10","doi-asserted-by":"publisher","first-page":"464","DOI":"10.1016\/j.ajic.2020.12.006","article-title":"Occurrence of respiratory viruses on school desks.","volume":"49","author":"Zulli","year":"2021","journal-title":"Am J Infect Control"},{"issue":"6","key":"zoi251022r11","doi-asserted-by":"publisher","DOI":"10.1111\/irv.13171","article-title":"Changing pattern of respiratory virus detections among school-aged children in a small community\u2014Dane County, Wisconsin, September to December 2022.","volume":"17","author":"Temte","year":"2023","journal-title":"Influenza Other Respir Viruses"},{"issue":"1","key":"zoi251022r12","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1111\/1574-6968.12487","article-title":"Challenges of studying viral aerosol metagenomics and communities in comparison with bacterial and fungal aerosols.","volume":"357","author":"Prussin","year":"2014","journal-title":"FEMS Microbiol Lett"},{"key":"zoi251022r13","doi-asserted-by":"publisher","DOI":"10.3389\/fpubh.2023.1208348","article-title":"Droplet digital PCR application for the detection of SARS-CoV-2 in air sample.","volume":"11","author":"Rashid","year":"2023","journal-title":"Front Public Health"},{"issue":"1","key":"zoi251022r14","doi-asserted-by":"publisher","first-page":"48","DOI":"10.1186\/s40246-024-00614-8","article-title":"Simultaneous detection of influenza A, B and respiratory syncytial virus in wastewater samples by one-step multiplex RT-ddPCR assay.","volume":"18","author":"Zafeiriadou","year":"2024","journal-title":"Hum Genomics"},{"issue":"9","key":"zoi251022r15","doi-asserted-by":"publisher","first-page":"839","DOI":"10.1001\/jama.2021.11559","article-title":"Effect of school integrated pest management or classroom air filter purifiers on asthma symptoms in students with active asthma: a randomized clinical trial.","volume":"326","author":"Phipatanakul","year":"2021","journal-title":"JAMA"},{"key":"zoi251022r16","doi-asserted-by":"publisher","DOI":"10.1016\/j.scitotenv.2023.164402","article-title":"Assessing the effectiveness of portable HEPA air cleaners for reducing particulate matter exposure in King County, Washington homeless shelters: implications for community congregate settings.","volume":"891","author":"Huang","year":"2023","journal-title":"Sci Total Environ"},{"issue":"4","key":"zoi251022r17","doi-asserted-by":"publisher","first-page":"644","DOI":"10.1038\/s41370-025-00743-9","article-title":"Classroom air quality in a randomized crossover trial with portable HEPA air cleaners.","volume":"35","author":"Simona","year":"2025","journal-title":"J Expo Sci Environ Epidemiol"},{"issue":"9","key":"zoi251022r18","doi-asserted-by":"publisher","first-page":"S102","DOI":"10.1016\/j.ajic.2016.06.003","article-title":"Airborne spread of infectious agents in the indoor environment.","volume":"44","author":"Wei","year":"2016","journal-title":"Am J Infect Control"},{"issue":"1","key":"zoi251022r19","doi-asserted-by":"publisher","first-page":"e97","DOI":"10.1093\/cid\/ciab933","article-title":"The removal of airborne Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and other microbial bioaerosols by air filtration on Coronavirus Disease 2019 (COVID-19) surge units.","volume":"75","author":"Conway Morris","year":"2022","journal-title":"Clin Infect Dis"},{"issue":"7","key":"zoi251022r20","doi-asserted-by":"publisher","DOI":"10.1136\/bmjopen-2023-072284","article-title":"Effect of portable HEPA filters on COVID-19 period prevalence: an observational quasi-interventional study in German kindergartens.","volume":"13","author":"Falkenberg","year":"2023","journal-title":"BMJ Open"},{"issue":"1","key":"zoi251022r21","doi-asserted-by":"publisher","first-page":"3487","DOI":"10.1038\/s41467-024-47777-5","article-title":"Ambient carbon dioxide concentration correlates with SARS-CoV-2 aerostability and infection risk.","volume":"15","author":"Haddrell","year":"2024","journal-title":"Nat Commun"},{"key":"zoi251022r22","doi-asserted-by":"publisher","first-page":"14","DOI":"10.1016\/j.cct.2017.06.008","article-title":"The school inner-city asthma intervention study: design, rationale, methods, and lessons learned.","volume":"60","author":"Phipatanakul","year":"2017","journal-title":"Contemp Clin Trials"},{"issue":"2","key":"zoi251022r23","doi-asserted-by":"publisher","first-page":"143","DOI":"10.1093\/annhyg\/mel073","article-title":"Physical collection efficiency of filter materials for bacteria and viruses.","volume":"51","author":"Burton","year":"2007","journal-title":"Ann Occup Hyg"},{"key":"zoi251022r24","doi-asserted-by":"publisher","DOI":"10.1016\/j.jobe.2020.101714","article-title":"Measurement of CO2 concentration for occupancy estimation in educational buildings with energy efficiency purposes.","volume":"32","author":"Franco","year":"2020","journal-title":"J Build Eng"},{"issue":"11","key":"zoi251022r25","doi-asserted-by":"publisher","DOI":"10.1001\/jamanetworkopen.2024.43769","article-title":"Air purifiers and acute respiratory infections in residential aged care: a randomized clinical trial.","volume":"7","author":"Thottiyil Sultanmuhammed Abdul Khadar","year":"2024","journal-title":"JAMA Netw Open"},{"issue":"1","key":"zoi251022r26","doi-asserted-by":"publisher","first-page":"1332","DOI":"10.1038\/s41467-023-36986-z","article-title":"Indoor air surveillance and factors associated with respiratory pathogen detection in community settings in Belgium.","volume":"14","author":"Raymenants","year":"2023","journal-title":"Nat Commun"},{"key":"zoi251022r27","doi-asserted-by":"publisher","DOI":"10.1016\/j.scitotenv.2021.144956","article-title":"Air filtration as a tool for the reduction of viral aerosols.","volume":"772","author":"Zacharias","year":"2021","journal-title":"Sci Total Environ"},{"key":"zoi251022r28","doi-asserted-by":"publisher","DOI":"10.1155\/2011\/734690","article-title":"The effects of temperature and relative humidity on the viability of the SARS coronavirus.","volume":"2011","author":"Chan","year":"2011","journal-title":"Adv Virol"},{"issue":"19","key":"zoi251022r29","doi-asserted-by":"publisher","first-page":"6781","DOI":"10.1128\/AEM.01658-12","article-title":"Mechanisms by which ambient humidity may affect viruses in aerosols.","volume":"78","author":"Yang","year":"2012","journal-title":"Appl Environ Microbiol"},{"issue":"1","key":"zoi251022r30","doi-asserted-by":"publisher","first-page":"11481","DOI":"10.1038\/s41598-022-15703-8","article-title":"Modeling the impact of indoor relative humidity on the infection risk of five respiratory airborne viruses.","volume":"12","author":"Aganovic","year":"2022","journal-title":"Sci Rep"},{"issue":"22","key":"zoi251022r31","doi-asserted-by":"publisher","first-page":"10905","DOI":"10.1073\/pnas.1902840116","article-title":"Low ambient humidity impairs barrier function and innate resistance against influenza infection.","volume":"116","author":"Kudo","year":"2019","journal-title":"Proc Natl Acad Sci U S A"},{"issue":"12","key":"zoi251022r32","first-page":"738","article-title":"School absenteeism in children and adolescents.","volume":"98","author":"Allen","year":"2018","journal-title":"Am Fam Physician"},{"key":"zoi251022r33","doi-asserted-by":"publisher","DOI":"10.1371\/currents.RRN1051","article-title":"Economic cost and health care workforce effects of school closures in the U.S.","volume":"1","author":"Lempel","year":"2009","journal-title":"PLoS Curr"},{"key":"zoi251022r34","doi-asserted-by":"publisher","DOI":"10.31478\/202306c","article-title":"Vital signs for pediatric health: chronic absenteeism.","volume":"2023:","author":"Johnson","year":"2023","journal-title":"NAM Perspect"}],"container-title":["JAMA Network Open"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/jamanetwork.com\/journals\/jamanetworkopen\/articlepdf\/2839930\/sun_2025_oi_251022_1759501447.84165.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T15:30:41Z","timestamp":1760110241000},"score":1,"resource":{"primary":{"URL":"https:\/\/jamanetwork.com\/journals\/jamanetworkopen\/fullarticle\/2839930"}},"subtitle":["A Secondary Analysis of a Randomized Clinical Trial"],"short-title":[],"issued":{"date-parts":[[2025,10,10]]},"references-count":34,"journal-issue":{"issue":"10","published-print":{"date-parts":[[2025,10,1]]}},"URL":"https:\/\/doi.org\/10.1001\/jamanetworkopen.2025.36951","relation":{},"ISSN":["2574-3805"],"issn-type":[{"value":"2574-3805","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,10,10]]}}}