The effectiveness of homemade masks is "not possible to assess" at this time, said the National Academies of Sciences, Engineering and Medicine in a letter to the White House.

The effectiveness of homemade masks is "not possible to assess" at this time, said the National Academies of Sciences, Engineering and Medicine in a letter to the White House. https://t.co/1QM0TuHXpf

— CNN (@CNN) April 10, 2020