The Mayo Clinic offers answers to your questions about face masks, including how to use them properly.
Can face masks help prevent the spread of coronavirus disease 2019 (COVID-19)? Yes, face masks combined with other preventive measures, such as frequent hand-washing and social distancing, help slow the spread of the disease.
So why weren't face masks recommended at the start of the pandemic? At that time, experts didn't yet 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 the U.S. Centers for Disease Control and Prevention (CDC) to do an about-face on face masks. The CDC updated its guidance to recommend widespread use of simple cloth face coverings to help prevent transmission of COVID-19 by people who have the virus but don't know it.
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