CDC publishes new evidence, updates guidance

Our new page on Mask Fit summarizes peer-reviewed evidence on improving mask fit, and integrates the new research, which found that double masking and a method of improving fit by knotting earloops and tucking in excess material both improved filtration. The researchers used disposable masks for the knot-and-tuck experiment and one disposable and an over-layered three-layer cloth mask for the double-masking experiment. We discuss how to apply these findings to cloth masks.

The updated CDC guidance can be found here; Health Canada's advice here; and WHO advice here.