dc.contributor.author
Näher, Anatol-Fiete
dc.contributor.author
Schulte-Althoff, Matthias
dc.contributor.author
Kopka, Marvin
dc.contributor.author
Balzer, Felix
dc.contributor.author
Pozo-Martin, Francisco
dc.date.accessioned
2025-07-03T16:01:45Z
dc.date.available
2025-07-03T16:01:45Z
dc.identifier.uri
https://refubium.fu-berlin.de/handle/fub188/48087
dc.identifier.uri
http://dx.doi.org/10.17169/refubium-47809
dc.description.abstract
Background:
The question of the utility of face masks in preventing acute respiratory infections has received renewed attention during the COVID-19 pandemic. However, given the inconclusive evidence from existing randomized controlled trials, evidence based on real-world data with high external validity is missing.
Objective:
To add real-world evidence, this study aims to examine whether mask mandates in 51 countries and mask recommendations in 10 countries increased self-reported face mask use and reduced SARS-CoV-2 reproduction numbers and COVID-19 case growth rates.
Methods:
We applied an event study approach to data pooled from four sources: (1) country-level information on self-reported mask use was obtained from the COVID-19 Trends and Impact Survey, (2) data from the Oxford COVID-19 Government Response Tracker provided information on face mask mandates and recommendations and any other nonpharmacological interventions implemented, (3) mobility indicators from Google’s Community Mobility Reports were also included, and (4) SARS-CoV-2 reproduction numbers and COVID-19 case growth rates were retrieved from the Our World in Data—COVID-19 data set.
Results:
Mandates increased mask use by 8.81 percentage points (P=.006) on average, and SARS-CoV-2 reproduction numbers declined on average by −0.31 units (P=.008). Although no significant average effect of mask mandates was observed for growth rates of COVID-19 cases (−0.98 percentage points; P=.56), the results indicate incremental effects on days 26 (−1.76 percentage points; P=.04), 27 (−1.89 percentage points; P=.05), 29 (−1.78 percentage points; P=.04), and 30 (−2.14 percentage points; P=.02) after mandate implementation. For self-reported face mask use and reproduction numbers, incremental effects are seen 6 and 13 days after mandate implementation. Both incremental effects persist for >30 days. Furthermore, mask recommendations increased self-reported mask use on average (5.84 percentage points; P<.001). However, there were no effects of recommendations on SARS-CoV-2 reproduction numbers or COVID-19 case growth rates (−0.06 units; P=.70 and −2.45 percentage points; P=.59). Single incremental effects on self-reported mask use were observed on days 11 (3.96 percentage points; P=.04), 13 (3.77 percentage points; P=.04) and 25 to 27 (4.20 percentage points; P=.048 and 5.91 percentage points; P=.01) after recommendation. Recommendations also affected reproduction numbers on days 0 (−0.07 units; P=.03) and 1 (−0.07 units; P=.03) and between days 21 (−0.09 units; P=.04) and 28 (−0.11 units; P=.05) and case growth rates between days 1 and 4 (−1.60 percentage points; P=.03 and −2.19 percentage points; P=.03) and on day 23 (−2.83 percentage points; P=.05) after publication.
Conclusions:
Contrary to recommendations, mask mandates can be used as an effective measure to reduce SARS-CoV-2 reproduction numbers. However, mandates alone are not sufficient to reduce growth rates of COVID-19 cases. Our study adds external validity to the existing randomized controlled trials on the effectiveness of face masks to reduce the spread of SARS-CoV-2.
en
dc.rights.uri
https://creativecommons.org/licenses/by/4.0/
dc.subject
nonpharmacological interventions
en
dc.subject
infectious diseases
en
dc.subject
acute respiratory infections
en
dc.subject
real-world evidence
en
dc.subject.ddc
600 Technik, Medizin, angewandte Wissenschaften::610 Medizin und Gesundheit::610 Medizin und Gesundheit
dc.title
Effects of Face Mask Mandates on COVID-19 Transmission in 51 Countries: Retrospective Event Study
dc.type
Wissenschaftlicher Artikel
dcterms.bibliographicCitation.articlenumber
e49307
dcterms.bibliographicCitation.doi
10.2196/49307
dcterms.bibliographicCitation.journaltitle
JMIR Public Health and Surveillance
dcterms.bibliographicCitation.originalpublishername
JMIR Publications
dcterms.bibliographicCitation.volume
10
refubium.affiliation
Charité - Universitätsmedizin Berlin
refubium.resourceType.isindependentpub
no
dcterms.accessRights.openaire
open access
dcterms.bibliographicCitation.pmid
38457225
dcterms.isPartOf.eissn
2369-2960