CDC study: Double masks block more particles

A new government study finds that wearing two masks can be better than one in protecting against coronavirus spread.

The Centers for Disease Control and Prevention on Wednesday reported the results of a lab experiment. The researchers found that particles were blocked twice as much when two masks were worn.

The CDC is updating its guidance to address wearing two masks. It says that a cloth mask worn over a surgical mask can tighten the gaps around the mask’s edges that can let virus particles in.

Does wearing two masks provide more protection?

The researchers found that wearing one mask — surgical or cloth — blocked around 40% of the particles coming in during an experiment. When a cloth mask was worn on top of a surgical mask, about 80% were blocked.

Some Americans have already started doubling up. Experts believe that’s at least partly out of concern about new strains of coronavirus that possibly spread more easily. The U.S. has registered 2.7 million confirmed cases and more than 468,000 confirmed deaths, the highest numbers in the world.