New study in @Health_Affairs: data suggest that the 15 states and DC that mandated mask-wearing in public between 4/8 and 5/15 averted as many as 230,000–450,000 #covid19 cases.

Wear your mask. Keep your distance. It's not politics; it's science. https://t.co/JUQNJg5DqH

— Zeke Emanuel (@ZekeEmanuel) June 17, 2020