Face masks don’t even have to work especially well to be effective

The group's model indicates that face masks don't have to be especially effective to slow the spread of SARS-CoV-2—as long as they limit the spread of the virus from infected people, they can limit the pandemic even if they make mask wearers more susceptible to infection.

The researchers also considered a scenario where wearing masks makes people more susceptible to infection, as they touch their face more often because of the mask's presence. While mask wearers suffer in this scenario, the population overall still benefits under most conditions in which at least two-thirds of the population is wearing masks.