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Mask-wearing significantly reduces COVID-19 incidence — Systematic review

Wearing masks is the single most effective public health measure against the coronavirus, cutting incidence by up to 53%, according to a systematic review and meta-analysis published in the British Medical Journal.

THE findings come as parts of the world increasingly loosen masking requirements, citing vaccine efficacy. However, experts have warned against lifting mask mandates too soon.

“This systematic review and meta analysis [of non-pharmaceutical interventions] suggests that several personal protective and social measures, including handwashing, mask-wearing, and physical distancing, are associated with reductions in the incidence of COVID-19,” wrote the researchers, affiliated with universities in Australia, Scotland and China.

While vaccines have proven safe and effective at saving lives, they do not offer 100% protection, especially in light of new variants, the study notes.

“Public health efforts to implement public health measures should consider community health and sociocultural needs, and future research is needed to better understand the effectiveness of public health measures in the context of COVID-19 vaccination.”

Study details

Effectiveness of public health measures in reducing the incidence of COVID-19, SARS-CoV-2 transmission, and COVID-19 mortality: systematic review and meta-analysis

Stella Talic, Shivangi Shah, Holly Wild, Danijela Gasevic, Ashika Maharaj, Zanfina Ademi, Xue Li, Wei Xu, Ines Mesa-Eguiagaray, Jasmin Rostron, Evropi Theodoratou, Xiaomeng Zhang, Ashmika Motee, Danny Liew, Dragan Ilic,

Published in British Medical Journal on 18 November 2021

Abstract

Objective
To review the evidence on the effectiveness of public health measures in reducing the incidence of covid-19, SARS-CoV-2 transmission, and covid-19 mortality. Observational and interventional studies that assessed the effectiveness of public health measures in reducing the incidence of COVID-19, SARS-CoV-2 transmission, and COVID-19 mortality.

Main outcome measures
The main outcome measure was incidence of COVID-19. Secondary outcomes included SARS-CoV-2 transmission and COVID-19 mortality.

Data synthesis
DerSimonian Laird random effects meta-analysis was performed to investigate the effect of mask wearing, handwashing, and physical distancing measures on incidence of covid-19. Pooled effect estimates with corresponding 95% confidence intervals were computed, and heterogeneity among studies was assessed using Cochran’s Q test and the I2 metrics, with two tailed P values.

Results
A total of 72 studies met the inclusion criteria, of which 35 evaluated individual public health measures and 37 assessed multiple public health measures as a “package of interventions”. Eight of 35 studies were included in the meta-analysis, which indicated a reduction in incidence of COVID-19 associated with handwashing (relative risk 0.47, 95% confidence interval 0.19 to 1.12, I2=12%), mask-wearing (0.47, 0.29 to 0.75, I2=84%), and physical distancing (0.75, 0.59 to 0.95, I2=87%). Owing to heterogeneity of the studies, meta-analysis was not possible for the outcomes of quarantine and isolation, universal lockdowns, and closures of borders, schools, and workplaces. The effects of these interventions were synthesised descriptively.

Conclusions
This systematic review and meta-analysis suggests that several personal protective and social measures, including handwashing, mask-wearing, and physical distancing are associated with reductions in the incidents of COVID-19. Public health efforts to implement public health measures should consider community health and socio-cultural needs, and future research is needed to better understand the effectiveness of public health measures in the context of COVID-19 vaccination.

 

BMJ article – Effectiveness of public health measures in reducing the incidence of COVID-19, SARS-CoV-2 transmission, and COVID-19 mortality: systematic review and meta-analysis (Open access)

 

See more from MedicalBrief archives:

 

Most blue surgical masks ineffective against COVID-19 — Canada study

 

Masks helped limit COVID transmission in unvaccinated students — US study

 

New CDC guideline admits that COVID-19 transmission is airborne

 

ECDC report: Face mask effectiveness in reducing COVID-19 transmission

 

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