Masks are effective at reducing COVID-19 primary transmission through respiratory droplets; the CDC acknowledges airborne transmission via aerosols can also occur
Current epidemiological data indicates that COVID-19 primarily spreads through respiratory droplets that are released when an infected person sneezes, coughs, or talks. Growing evidence suggests that smaller aerosol particles may also play a role in the transmission of COVID-19. Wearing face masks and cloth face coverings are effective measures for reducing the spread of COVID-19 because they reduce the transmission of large respiratory droplets. In contrast, some aerosol particles may leak through the fabric pores and around the mask. To reduce the risk of COVID-19 infection, wearing face masks must be combined with other transmission control measures, such as physical distancing, good hand hygiene, and avoiding crowded and poorly ventilated spaces.