Fast Five Quiz: COVID-19 Prevention

Michael Stuart Bronze, MD


December 16, 2022

In a study that aimed to estimate the value of maintaining masking indoors according to different COVID-19 vaccination coverage levels, face mask use was determined to be cost-effective for about 2-10 weeks after target vaccination coverage (70%-90%). This duration was longer during winter vs summer. The authors note that factors that might increase virus transmissibility (ie, new variants) or decrease vaccine effectiveness (ie, waning immunity) should encourage continued behavioral mitigation strategies.

Mask wearing in community settings has been shown to effectively reduce disease transmission.

A cluster randomized trial concluded that community-level mask distribution decreased symptomatic seroprevalence, particularly among adults aged ≥ 60 years in areas where surgical masks were distributed. Indeed, the same clinical trial notes that surgical masks have been proven superior to cloth face coverings; however, well-fitting KN-95 masks or N-95 respirators are widely considered much more effective than other types of masks in reducing transmission of COVID-19. These masks can provide a better seal and filter out small aerosols at a very high rate.

COVID-19 transmission has been found to be lower with physical distancing ≥ 1 m, with protection increasing as distance lengthens. A 2022 study found that in people wearing face masks, social distancing could be reduced to 0.5 m without increasing the inhaled mass concentration of particles. The authors emphasize that when physical distancing proves difficult, masking remains an effective mitigation strategy.

Learn more about the COVID-19 route of transmission.


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