Face masks for preventing respiratory infections in the community: A systematic review

Background The Ministry of Social Affairs and Health in Finland commissioned this systematic literature review on the effectiveness and safety of using face masks in public environments in protecting against upper respiratory tract infections, to inform policy. Previous reviews have not clearly distinguished the context of mask use. Methods The review was completed within two weeks, adhering to the PRISMA guidelines where possible. The review looks at the effect of face coverings (surgical masks or cloth coverings, excluding FFP2 and FFP3 masks) in protecting against the transmission in droplet-mediated respiratory tract infections. Our review includes controlled trials or previous systematic reviews of mask use by the general public in public spaces, outside homes and healthcare facilities. Results The systematic literature search identified five randomized trials. Use of masks prevented infections in one subgroup of one pilot study, so the effect of face masks on the transmission of infections outside the home appears small or nonexistent. Five of the eight systematic reviews showed no evidence of face masks being helpful in controlling the spread of respiratory infection or preventing exposure in healthy individuals. Meta-analyses often combined very heterogeneous studies and costs were not reported in any studies. Conclusions Randomized studies on the effect of face coverings in the general population are few. The reported effect of masks used outside the home on transmission of droplet-mediated respiratory infections in the population is minimal or non-existent. It is difficult to distinguish the potential effect of masks from the effects of other protective measures. What is already known on this subject? Previous reviews on the effectiveness and safety of use of face masks in protecting against upper respiratory tract infections have not clearly distinguished the context of mask use. They have combined very heterogeneous studies done in homes, health care settings, or public environments. What does this study add? Our systematic review on the use of face masks in public environments, done to inform an impending policy decision, found five randomized trials (RCTs) and eight reviews. Use of masks prevented infections in one subgroup of one RCT, so the effect of face masks appears small or nonexistent. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement The Ministry of Social Affairs and Health in Finland commissioned and funded the review, participated in the formulation of the study question, and requested that only randomized trials and systematic reviews are included. The Ministry has otherwise not influenced the methodology, analysis, interpretation, conclusions, or any other aspects of the review. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: No approvals for the work were necessary. All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data relevant to the study are included in the article or uploaded as supplementary information