A study says it's likely that face masks, by blocking even some of the virus-carrying droplets one inhales, can reduce the risk of falling seriously ill from COVID-19 by reducing the amount of infection a person is exposed to. According to Monica Gandhi, an infectious disease specialist at University of California, San Francisco, this has the potential of variolation, that is, getting a milder infection that protects a person from a more serious infection as the world awaits a vaccine.