The recommendation to wear surgical masks to supplement other public health measures did not reduce the SARS-CoV-2 infection rate among wearers by more than 50% in a community with modest infection rates, some degree of social distancing, and uncommon general mask use.
The takeaway: While minimal protection occurs when a mask is worn in a place where many others are not wearing a mask, community masking is associated with a reduction in COVID cases.
The claim: In a community with modest infection rates, some social distancing, and most people not wearing masks, wearing a surgical mask did not reduce the SARS-CoV-2 infection rate by more than 50%.
The evidence: This study showed that wearing a mask in a community where most people did not wear a mask, did not reduce the risk of getting infected by 50%. Fewer COVID infections were reported in the mask group than in the unmasked group. This study agrees with a meta analysis which showed that masks resulted in a decrease in infections but did not prevent all infections (1) According to the CDC, seven studies have shown community level benefit when masking recommendations were made (2).
When most in the community are not wearing masks, social distancing, and washing hands, wearing a mask alone provides minimal protection to the mask wearer. Community wide masking is associated with a reduction in COVID cases (2).
Sources:
1) https://pubmed.ncbi.nlm.nih.gov/29140516/
2) https://www.cdc.gov/coronavirus/2019-ncov/more/masking-science-sars-cov2.html