A study of more than 2,900 healthcare workers in Switzerland found those who reported using respirator masks were 40 percent less likely to contract COVID-19 than those wearing surgical masks after being exposed to COVID-19 patients.
The findings were published Aug. 15 in JAMA Network Open and involved 2,919 healthcare workers across seven healthcare networks in Switzerland from September 2020 to September 2021. Researchers asked participants which type of mask — surgical, respirator or a mix of both — they normally used during contact with COVID-19 patients, "outside of aerosol-generating procedures." To assess cumulative patient exposure, researchers multiplied participants' self-reported number of contacts with COVID-19 patients by the mean duration of the contact.
A total of 749 participants, or 26 percent, tested positive for COVID-19 during the study period. Among healthcare workers who were exposed to infected patients, the test positivity rate was 21 percent for those who said they only used respirator masks and 35 percent for those who used surgical or mixed masks.
"The odds of being SARS-CoV-2-positive were reduced by more than 40 percent in individuals using respirators irrespective of cumulative exposure, even after adjusting for multiple work- and nonwork-related covariables," researchers said. It's uncertain whether the risk reduction observed in the study, which took place before omicron was widespread, is applicable amid the spread of newer variants, researchers added.
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