The Centers for Disease Control and Prevention (CDC) updated its mask guidance on Wednesday to include data from a recent lab experiment that found placing a cloth mask over a surgical mask, as well as using a properly fitted mask, was effective in stopping coronavirus spread.
The update, which was announced by CDC Director Dr. Rochelle Walensky during a White House coronavirus briefing, comes after a lab experiment using simulated respiratory breaths found that placing a cloth mask over a medical procedure mask or using a medical procedure mask with knotted ear loops and tucked in sides decreased exposure to potentially infectious aerosols by about 95%.
