{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,15]],"date-time":"2026-07-15T05:07:01Z","timestamp":1784092021434,"version":"3.55.0"},"reference-count":26,"publisher":"Oxford University Press (OUP)","issue":"2","license":[{"start":{"date-parts":[[2025,10,22]],"date-time":"2025-10-22T00:00:00Z","timestamp":1761091200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100001263","name":"National Philanthropic Trust","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100001263","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100019228","name":"Tides Foundation","doi-asserted-by":"publisher","award":["TF2008-094054"],"award-info":[{"award-number":["TF2008-094054"]}],"id":[{"id":"10.13039\/100019228","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["K23 DK120899"],"award-info":[{"award-number":["K23 DK120899"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,2,5]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Despite widespread implementation of mask mandates for COVID-19 transmission control, studies examining their effectiveness have yielded mixed results ranging from strong benefits to no effect. These inconsistencies may arise from a variety of methodological and measurement challenges, including the implicit assumption that mandates truly modify masking behavior\u2014the essential mechanism for transmission interruption. Here, we leverage self-reported mask adherence data from &amp;gt;34\u2009000 individuals collected via a digital participatory surveillance platform between June 2, 2020, and January 1, 2021, to examine this assumption. Using an interrupted time series approach, we aggregate masking observations at the county level to analyze the effect of mandates on masking uptake across 555 diverse U.S. counties. We evaluate masking during the 14\u00a0days premandate and postmandate issuance, finding a modest 1-3 percentage point overall increases in masking. However, substantial heterogeneity was observed, with larger changes seen in counties initially exhibiting low mask adherence, the U.S. West, and on masking uptake in public compared to private settings. Our findings suggest that conflicting estimates of the effect of mandates on transmission reduction may reflect modification by heterogeneity in the mandates\u2019 alteration of masking behavior. Future interventions should tailor mandates to local context and baseline adherence for maximal behavioral change.<\/jats:p>","DOI":"10.1093\/aje\/kwaf236","type":"journal-article","created":{"date-parts":[[2025,10,21]],"date-time":"2025-10-21T11:37:31Z","timestamp":1761046651000},"page":"488-496","source":"Crossref","is-referenced-by-count":0,"title":["Heterogeneous impact of mask mandates on U.S. masking behavior: an interrupted time series study"],"prefix":"10.1093","volume":"195","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6095-0193","authenticated-orcid":false,"given":"Benjamin","family":"Rader","sequence":"first","affiliation":[{"name":"Department of Epidemiology, Boston University School of Public Health , Boston, MA ,","place":["United States"]},{"name":"Innovation and Digital Health Accelerator, Boston Children\u2019s Hospital , Boston, MA ,","place":["United States"]},{"name":"Department of Anesthesiology, Harvard Medical School , Boston, MA ,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5063-8470","authenticated-orcid":false,"given":"Christina M","family":"Astley","sequence":"additional","affiliation":[{"name":"Innovation and Digital Health Accelerator, Boston Children\u2019s Hospital , Boston, MA ,","place":["United States"]},{"name":"Division of Endocrinology, Boston Children\u2019s Hospital , Boston, MA ,","place":["United States"]},{"name":"Department of Pediatrics, Harvard Medical School , Boston, MA ,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0588-8235","authenticated-orcid":false,"given":"Laura F","family":"White","sequence":"additional","affiliation":[{"name":"Department of Biostatistics, Boston University School of Public Health , Boston, MA ,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8568-5317","authenticated-orcid":false,"given":"John S","family":"Brownstein","sequence":"additional","affiliation":[{"name":"Innovation and Digital Health Accelerator, Boston Children\u2019s Hospital , Boston, MA ,","place":["United States"]},{"name":"Department of Pediatrics, Harvard Medical School , Boston, MA ,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9887-0634","authenticated-orcid":false,"given":"Matthew P","family":"Fox","sequence":"additional","affiliation":[{"name":"Department of Epidemiology, Boston University School of Public Health , Boston, MA ,","place":["United States"]},{"name":"Department of Global Health, Boston University School of Public Health , Boston, MA ,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2025,10,22]]},"reference":[{"key":"2026071500365747500_ref1","volume-title":"The New York Times","author":"Katz","year":"2020"},{"issue":"4","key":"2026071500365747500_ref2","doi-asserted-by":"publisher","DOI":"10.1002\/14651858.CD006207.pub6","article-title":"Physical interventions to interrupt or reduce the spread of respiratory viruses","volume":"2023","author":"Jefferson","year":"2023","journal-title":"Cochrane Database Syst Rev"},{"issue":"2","key":"2026071500365747500_ref3","doi-asserted-by":"publisher","DOI":"10.1126\/sciadv.abd7204","article-title":"Partisan pandemic: how partisanship and public health concerns affect individuals\u2019 social mobility during COVID-19","volume":"7","author":"Clinton","year":"2021","journal-title":"Sci Adv."},{"key":"2026071500365747500_ref4","volume-title":"BBC News","author":"McKelvey","year":"2020"},{"issue":"3","key":"2026071500365747500_ref5","doi-asserted-by":"publisher","first-page":"e148","DOI":"10.1016\/S2589-7500(20)30293-4","article-title":"Mask-wearing and control of SARS-CoV-2 transmission in the USA: a cross-sectional study","volume":"3","author":"Rader","year":"2021","journal-title":"Lancet Digi Health."},{"issue":"4","key":"2026071500365747500_ref6","doi-asserted-by":"publisher","first-page":"449","DOI":"10.1017\/S0950268809991658","article-title":"Face masks to prevent transmission of influenza virus: a systematic review","volume":"138","author":"Cowling","year":"2010","journal-title":"Epidemiol Infect."},{"issue":"28","key":"2026071500365747500_ref7","doi-asserted-by":"publisher","first-page":"930","DOI":"10.15585\/mmwr.mm6928e2","article-title":"Absence of apparent transmission of SARS-CoV-2 from two stylists after exposure at a hair salon with a universal face covering policy\u2014Springfield, Missouri, May 2020","volume":"69","author":"Hendrix","year":"2020","journal-title":"MMWR Morb Mortal Wkly Rep."},{"issue":"7","key":"2026071500365747500_ref8","doi-asserted-by":"publisher","first-page":"703","DOI":"10.1001\/jama.2020.12897","article-title":"Association between universal masking in a health care system and SARS-CoV-2 positivity among health care workers","volume":"324","author":"Wang","year":"2020","journal-title":"JAMA."},{"issue":"23","key":"2026071500365747500_ref9","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.2119266119","article-title":"Mask wearing in community settings reduces SARS-CoV-2 transmission","volume":"119","author":"Leech","year":"2022","journal-title":"Proc Natl Acad Sci USA."},{"issue":"6531","key":"2026071500365747500_ref10","doi-asserted-by":"publisher","DOI":"10.1126\/science.abd9338","article-title":"Inferring the effectiveness of government interventions against COVID-19","volume":"371","author":"Brauner","year":"2021","journal-title":"Science."},{"issue":"10","key":"2026071500365747500_ref11","doi-asserted-by":"publisher","first-page":"350","DOI":"10.15585\/mmwr.mm7010e3","article-title":"Association of state-issued mask mandates and allowing on-premises restaurant dining with county-level COVID-19 case and death growth rates\u2014United States, March 1 to December 31, 2020","volume":"70","author":"Guy","year":"2021","journal-title":"MMWR Morb Mortal Wkly Rep."},{"issue":"21","key":"2026071500365747500_ref12","doi-asserted-by":"publisher","first-page":"1935","DOI":"10.1056\/NEJMoa2211029","article-title":"Lifting universal masking in schools: Covid-19 incidence among students and staff","volume":"387","author":"Cowger","year":"2022","journal-title":"N Engl J Med."},{"issue":"4","key":"2026071500365747500_ref13","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0249891","article-title":"Mask adherence and rate of COVID-19 across the United States","volume":"16","author":"Fischer","year":"2021","journal-title":"PloS One."},{"issue":"6","key":"2026071500365747500_ref14","doi-asserted-by":"publisher","first-page":"21250132","DOI":"10.1371\/journal.pone.0252315","article-title":"Association between covid-19 outcomes and mask mandates, adherence, and attitudes","volume":"16","author":"Adjodah","year":"2021","journal-title":"PloS One."},{"issue":"8","key":"2026071500365747500_ref15","doi-asserted-by":"publisher","first-page":"1090","DOI":"10.1001\/jamainternmed.2021.2915","article-title":"Assessing the association between social gatherings and COVID-19 risk using birthdays","volume":"181","author":"Whaley","year":"2021","journal-title":"JAMA Intern Med."},{"issue":"11","key":"2026071500365747500_ref16","doi-asserted-by":"publisher","first-page":"2474","DOI":"10.1093\/aje\/kwab185","article-title":"COVID-19 policy impact evaluation: a guide to common design issues","volume":"190","author":"Haber","year":"2021","journal-title":"Am J Epidemiol."},{"key":"2026071500365747500_ref17","first-page":"1","volume-title":"National Highway Traffic Safety Administration","author":"Hedlund","year":"2008"},{"issue":"4","key":"2026071500365747500_ref18","doi-asserted-by":"publisher","first-page":"828","DOI":"10.1162\/003465303772815754","article-title":"The effects of mandatory seat belt laws on driving behavior and traffic fatalities","volume":"85","author":"Cohen","year":"2003","journal-title":"Rev Econ Stat."},{"key":"2026071500365747500_ref19","doi-asserted-by":"publisher","DOI":"10.2139\/ssrn.3667149","article-title":"Tracking mask mandates during the Covid-19 pandemic","author":"Wright","year":"2020","journal-title":"SSRN Electron J."},{"key":"2026071500365747500_ref20","article-title":"Coronavirus in Ohio: DeWine requires masks in seven counties, including Cuyahoga","author":"Ludlow","year":"2020","journal-title":"Akron Beacon Journal"},{"issue":"13","key":"2026071500365747500_ref21","doi-asserted-by":"publisher","first-page":"489","DOI":"10.15585\/mmwr.mm7113e1","article-title":"Use of at-home COVID-19 tests\u2014United States, August 23, 2021 to March 12, 2022","volume":"71","author":"Rader","year":"2022","journal-title":"MMWR Morb Mortal Wkly Rep."},{"issue":"5","key":"2026071500365747500_ref22","doi-asserted-by":"publisher","first-page":"603","DOI":"10.1016\/S1473-3099(22)00001-9","article-title":"Generation time of the alpha and delta SARS-CoV-2 variants: an epidemiological analysis","volume":"22","author":"Hart","year":"2022","journal-title":"Lancet Infect Dis."},{"issue":"4","key":"2026071500365747500_ref23","doi-asserted-by":"publisher","first-page":"299","DOI":"10.1046\/j.1365-2710.2002.00430.x","article-title":"Segmented regression analysis of interrupted time series studies in medication use research","volume":"27","author":"Wagner","year":"2002","journal-title":"J Clin Pharm Ther."},{"issue":"26","key":"2026071500365747500_ref24","doi-asserted-by":"publisher","first-page":"772","DOI":"10.21105\/joss.00772","article-title":"ggeffects: Tidy data frames of marginal effects from regression models","volume":"3","author":"L\u00fcdecke","year":"2018","journal-title":"J Open Sourc Softw."},{"issue":"7","key":"2026071500365747500_ref25","doi-asserted-by":"publisher","first-page":"702","DOI":"10.1093\/aje\/kwh090","article-title":"A modified Poisson regression approach to prospective studies with binary data","volume":"159","author":"Zou","year":"2004","journal-title":"Am J Epidemiol."},{"key":"2026071500365747500_ref26","volume-title":"2015-2019 American Community Survey","author":"U.S. Census Bureau","year":"2021"}],"container-title":["American Journal of Epidemiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/academic.oup.com\/aje\/advance-article-pdf\/doi\/10.1093\/aje\/kwaf236\/64837501\/kwaf236.pdf","content-type":"application\/pdf","content-version":"am","intended-application":"syndication"},{"URL":"https:\/\/academic.oup.com\/aje\/article-pdf\/195\/2\/488\/64837501\/kwaf236.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/academic.oup.com\/aje\/article-pdf\/195\/2\/488\/64837501\/kwaf236.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,15]],"date-time":"2026-07-15T04:37:26Z","timestamp":1784090246000},"score":1,"resource":{"primary":{"URL":"https:\/\/academic.oup.com\/aje\/article\/195\/2\/488\/8295631"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,10,22]]},"references-count":26,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2025,10,22]]},"published-print":{"date-parts":[[2026,2,5]]}},"URL":"https:\/\/doi.org\/10.1093\/aje\/kwaf236","relation":{},"ISSN":["0002-9262","1476-6256"],"issn-type":[{"value":"0002-9262","type":"print"},{"value":"1476-6256","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[2026,2]]},"published":{"date-parts":[[2025,10,22]]}}}