COVID-19: How much protection do face masks offer?


face masks combined with other preventive measures, such as frequent hand-washing and social distancing, help slow the spread of the virus.

At that time, experts didn’t know the extent to which people with COVID-19 could spread the virus before symptoms appeared. Nor was it known that some people have COVID-19 but don’t have any symptoms. Both groups can unknowingly spread the virus to others.

These discoveries led public health groups to do an about-face on face masks. The World Health Organization and the U.S. Centers for Disease Control and Prevention (CDC) now include face masks in their recommendations for slowing the spread of the virus. The CDC recommends cloth face masks for the public and not the surgical and N95 masks needed by health care providers.