There’s some evidence that caretakers of infected people can protect their health by wearing masks, the WHO guidance said, but “there is currently no evidence that wearing a mask (whether medical or other types) by healthy persons in the wider community setting, including universal community masking, can prevent them from infection with respiratory viruses, including COVID-19.”
https://www.businessinsider.com/who-no-need-for-healthy-people-to-wear-face-masks-2020-4