Masks can’t reduce Covid infection rates or transmission of any virus: Petty
Viruses travel in aerosols that stay suspended in air up to 50 days
Industrial hygienist Stephen Petty gave excellent testimony in the New Hampshire Senate on how masks don’t block aerosols and can’t reduce viral infection rates.
(His PDF handout is here.)
Unfortunately, many doctors who haven’t had time to read the studies rely on government officials or health administrators issuing scientifically unsupportable masking mandates.