On Wednesday, the US CDC (Centers for Disease Control and Prevention) has announced new guidelines. The move came after months of demands for federal health officials to update mask recommendations. The new guidelines include wearing well-fitting face masks or two masks at a time to help curb the COVID-19 pandemic. The updated guidance follows the release of new research from the CDC which tested various masks in a lab setting. It found evidence that combining a cloth mask over a surgical mask could dramatically decrease both the spread of the virus to others and exposure to the virus oneself. The CDC’s new recommendations advise Americans to select masks with a nose wire that can be adjusted for a snug fit and use a mask fitter or brace to better seal their masks.
The CDC also recommended wearing a mask with multiple layers for greater protection or layering a cloth mask over a disposable medical mask. The agency doesn’t recommend wearing two disposable masks at a time. And it says there is no need to layer another mask with a KN95 mask, the commonly-used alternative to the professional-grade N95 masks used by health care workers and first responders. CDC Director Rochelle Walensky said, “I want to be clear that these new scientific data released today do not change the specific recommendations about who should wear a mask or when they should wear one. But they do provide new information on why wearing a well-fitting mask is so important”. CDC researchers tested the combination in the new study of multi-layered cloth and common surgical or medical procedures masks in a laboratory, simulating breathing and coughing between pairs of dummies.
It is noteworthy that just 42% of cough droplets were blocked in the experiment when only a disposable mask was worn. Combining the disposable mask with a cloth mask on top blocked 92.5% of particles expelled from the cough. Combining the two masks also reduced the wearer’s “cumulative exposure” by 83% from droplets spread by an unmasked source. That number rose to 96.4% if both dummies were fitted with double masks. The agency’s top officials had rejected to change their official recommendations until this new research had been completed. A handful of health authorities have directed citizens to move away from cloth masks altogether in favor of single-use, high-filtration masks. Germany’s government-mandated “medical masks,” like surgical or KN95 masks, in public transit and stores last month.