If a medical procedure mask is worn alone, the CDC says modifications to improve the fit, such as knotting the ear loops and tucking in the sides of the mask, or wearing a cloth mask over it, can reduce exposure. Other options include using a “mask fitter” device or a sleeve made of nylon pantyhose to hold the mask tightly to the face, the agency said.
The background: The study is the latest to show evidence that masks can reduce transmission. The CDC last week released a pair of studies, including one that showed masks had helped slow hospitalizations in states that mandated their use.
The new research also comes as a growing number of experts — including Biden’s chief medical adviser, Anthony Fauci — have recommended double-masking to increase protection against Covid-19. The advice has been driven in part by the arrival in the U.S. of coronavirus variants that are more transmissible than earlier versions of the virus.
The Biden administration has urged Americans to wear masks when they are around people who don’t live in their households. The president has used executive orders to mandate masks in federal buildings and on public transportation, and at least a dozen states have imposed their own mask mandates.
What’s next: Biden administration officials are expected to discuss the findings at an 11 a.m. Covid-19 briefing Wednesday.