This systematic review and meta-analysis found that low certainty evidence suggests that medical masks and N95 respirators offer similar protection against viral respiratory infection in health care workers conducting non-aerosol generating care. Preservation of N95 respirators for high-risk, aerosol-generating procedures in this pandemic should be considered.

Although masks are critical in protecting health care workers at high risk of COVID-19, recommendations are conflicting and epidemiological data on their relative effectiveness are limited. This systematic review and meta-analysis compared medical masks to N95 respirators in preventing infection and respiratory illness in health care workers.

Researchers collected randomized controlled trials comparing the protective effect of medical masks to N95 respirators in health care workers. N95 respirators and medical masks were somewhat equivalent in preventing respiratory infection and clinical respiratory illness, although the certainty of the evidence was low and very low, respectively. Only one trial evaluated coronaviruses specifically and found no difference.