Danish study finds that face masks provide only limited protection against SARS-CoV-19 infection. Researchers say findings should not be used to argue against widespread use to prevent people from infecting others. After one month, 1.8% of people wearing the masks had been infected, while 2.1% in a control group. Health experts have long said a mask provides only limited protection for the person wearing it but can dramatically reduce others’ risk.

Reference
Danish study finds face masks provide limited protection …. https://www.swissinfo.ch/eng/reuters/danish-study-finds-face-masks-provide-moderate-to-no-protection-against-covid-19/46169826