CDC Says Masks Must Fit Tightly And Two Are Better Than One On Feb. 10, the Centers for Disease Control and Prevention released new mask guidelines based on a study of how mask fit affects the wearer’s exposure to airborne particles. With more transmissible COVID-19 strains emerging around the world, it is important to properly use the right kinds of face masks. Please share this article - Go to very top of page, right hand side, for social media buttons. Some practices - such as taking your mask off to speak or wearing your mask below your nose - are clearly problematic. Other mistakes may be less obvious. Everyone still needs to be wearing masks as much as possible - even if you’ve been vaccinated or have previously been infected with COVID - 19. So how do you get the most out of a mask?