CDC study: 2 masks and tighter fit could reduce COVID-19 exposure by up to 96% and last updated 2021-02-10 14:55:02-05 Masks and facial coverings are required in most settings to slow the spread of the coronavirus. The CDC released new data Wednesday on how to improve mask fit that reduces a personâs exposure to the virus by as much as 96%. It comes down to reducing gaps, by CDCâs study looked at what impact, if any, these simple methods had on slowing the spread. Coronavirus is spread from person-to-person through droplets in the air when an infected person speaks, coughs, sings, yells, breaths, etc. and those droplets are inhaled by others near them.