Selecting the best type of mask to double up on layers Janet Loehrke and George Petras, USA TODAY Published 5:04 pm UTC Feb. 10, 2021 One mask provides good protection against spreading the coronavirus, but two masks could offer more. As more-contagious variations of the virus are discovered, the notion of doubling up on masks is gaining traction, especially for those likely to become severely ill if they get infected. The Centers for Disease Control and Prevention released new research on Wednesday that double-masking or wearing tightly fitted medical masks can reduce exposure to infectious aerosols up to 95%. Leading health experts say fit and materials determine masks' efficacy against coronavirus transmission. Poorly fitted masks can allow air leaks around the nose and mouth. Materials that are too thin are less effective at blocking particles in the air.