A 2019 World Health Organization review of numerous studies testing the efficacy of face coverings to stop the transmission of influenza found “no evidence that [wearing a mask] is effective in reducing transmission” of the virus. The organization has further discouraged individuals from using cloth masks to cover their faces during pandemics, though at times that advice has appeared to shift.
The 2019 review was part of a larger study examining “non-pharmaceutical public health measures for mitigating the risk and impact of epidemic and pandemic influenza.” That paper effected a “systematic review of the evidence on the effectiveness of [non-pharmaceutical interventions], including personal protective measures, environmental measures, social distancing measures and travel-related measures.”
Among the measures the study reviewed were hand-washing, quarantine protocols, school closures, “respiratory etiquette” and face masks.
The document reviews 10 separate randomized, controlled trials examining the effectiveness of face masks in stopping flu transmission. There was “no evidence that face masks are effective in reducing transmission of laboratory-confirmed influenza” found in that survey.
Of the surveyed studies, just two found any reduction at all in the rate of influenza-like illnesses among participants; in one, the reduction occurred over a two-week period during a five-month study, while reductions in another “were not statistically significant.”
The review’s authors note that “the majority of these studies were conducted in households in which at least one person was infected, and exposure levels might be relatively higher.” Therefore, “additional studies of face mask use in the general community would be valuable.”…
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