The U.S. Centres for Disease Control and Prevention has long advised people to wear masks because they help prevent people who are infected – whether they know it or not – from spreading the coronavirus.
The CDC added a new reason: masks can also protect wearers who are not infected, though to a lesser degree.
The agency referred to a study led by Japanese researchers that found masks block about 60 percent of the amount of virus that comes out of an infected person. When an uninfected person wearing a mask is near an infected person who isn’t wearing one, the amount of virus the uninfected person inhaled fell by up to 50 percent.
But when both people are wearing masks that produced the best result. The decline in virus particles reaching the second person was close to 70 percent.
So, if everyone wears a mask when social distancing is not feasible, the infection rate will be cut, experts say.
It’s not a perfect solution. Hand-washing, keeping a distance and being in well-ventilated areas are all important.
Explainer: What’s with the confusion over masks? (AP)
CDC: Wearing a mask could keep you from catching virus (AP)
Japan researchers show masks do block coronavirus, but not perfectly (Reuters)
Effectiveness of face masks in preventing airborne transmission of SARS-CoV-2 (ASM)