The science is clear. Wearing a face mask is one of the best ways to prevent coronavirus transmission. The US Centers for Disease Control and Prevention recommends that people wear face masks both to protect others and to protect themselves.

Noting that behavior change takes time, Dr. Joshua Barocas, an infectious diseases physician at Boston Medical Center, says wearing a mask can help reduce transmission, help form a good habit and serve as a sign of respect.

On Sunday, first lady Melania Trump posted a video of herself wearing a mask during a visit to The Mary Elizabeth House, an organization supporting single mothers and their families.

The actor Tom Hanks, one of the first well-known public figures to announce he had contracted coronavirus, recently said he has “no respect” for people who don’t wear face masks in public.