If you missed it, the CDC released the results of its new mask study this week that shows the importance of a well-fitting mask. The researchers used dummies to experiment with two different methods that substantially improved mask performance. One was to knot the ear loops of a medical procedure mask where they attach to its edges and then tuck in and flatten the extra material close to the face (to minimize the side gaps). Another was to fit a cloth mask over a medical procedure mask. When either option was worn by both the source and receiver, exposure was reduced by about 95%.
Another good reminder from the CDC: Until vaccines help us achieve population immunity, universal masking is highly effective for slowing the spread of the virus when you combine it with other measures such as social distancing, avoiding crowds, avoiding poorly ventilated indoor areas, and washing your hands frequently and thoroughly.