The Centers for Disease Control and Prevention released new research on Feb. 10 that found wearing a cloth mask over a surgical mask offers substantially more protection against the coronavirus, as does tying knots on the ear loops of surgical masks to make the mask fit tighter. 

Wearing a mask alone is not enough: everyone should double-mask when going outside and make sure their disposable masks are securely fitted to their face.

In lab tests, exposure to infectious aerosols decreased by 92.5% with two masks compared to just one. A medical mask looped and knotted around a person’s ears can block 63% of particles that could contain coronavirus from escaping, a significant improvement from blocking only 42% of particles when unknotted. When both an infected and uninfected source wear double masks, the cumulative exposure from potentially infectious aerosols of the uninfected person was reduced by 96.4%.

The significant benefit of double-masking makes it a good idea to wear a cloth mask over your standard face mask to prevent the spread of the virus until the United States reaches herd immunity. Additionally, knot disposable masks around your ears and make sure they snugly fit on your face to minimize the chance of infecting someone else.