Cloth face masks should not be used in places where social distancing is impossible

Objectives:
During the ongoing COVID-19 pandemic, face masks are among the most common and practical control measures used globally in reducing the risk of infection and disease transmission. Although several studies have investigated the efficacy of various face masks and respirators in preventing infection, the results have been inconsistent. Therefore, this review article has been conducted.

What is the efficacy of various face masks and respirators in preventing infection?

Study design:
This review article included 16 randomized-controlled trials (RCTs) involving 17,048 individuals.

Results and conclusions:   
The investigators found, overall, evidence was weak, lacking statistical power due to the small number of participants and there was substantial inconsistency in these findings.

The investigators found in comparison to those without face masks, participants with fit-tested N95 respirators were likely to have lesser infection risk [RR = 0.67, 95% CI = 0.38 to 1.19, p = 0.80], followed by those with non-fit-tested N95 and non-fit-tested FFP2 respirators that shared the similar risk, [RR = 0.73, 95% CI = 0.12 to 4.36,p = 0.63] and [RR = 0.80, 95% CI = 0.38 to 1.71, p = 0.63], respectively.

The investigators found participants who donned face masks with and without hand hygiene practices showed modest risk improvement alike [RR = 0.89, 95% CI = 0.67 to 1.17, p = ]0.55) and [RR = 0.92, 95% CI = 0.70 to 1.22, p = 0.51].

The investigators found, otherwise, participants donning double-layered cloth masks were prone to infection [RR = 4.80, 95% CI = 1.42 to 16.27, p = 0.01].

The investigators found 11 out of 16 RCTs that underwent a pairwise meta-analysis revealed a substantially lower infection risk in those donning medical face masks (MFMs) than those without face masks [RR = 0.83, 95% CI = 0.71 to 0.96].

The investigators concluded that medical face masks lower infection risk and cloth face masks should not be used in the outbreak hot spots and places where social distancing is impossible.

Original title:
Efficacy of face masks against respiratory infectious diseases: a systematic review and network analysis of randomized-controlled trials by Tran TQ, Mostafa EM, […], Hirayama K.

Link:
https://pubmed.ncbi.nlm.nih.gov/34407516/

Additional information of El Mondo:
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