A patient adjusts his face mask as he leaves a COVID-19 vaccination site inside the Jacob K. Javits Convention Center, Wednesday, Feb. 3, 2021, in the Manhattan borough of New York. (AP Photo/John Minchillo)

A patient adjusts his face mask as he leaves a COVID-19 vaccination site inside the Jacob K. Javits Convention Center, Wednesday, Feb. 3, 2021, in the Manhattan borough of New York. (AP Photo/John Minchillo)

U.S. CDC study finds two masks are better than one vs. COVID-19

When both exhaling and inhaling heads were double-masked, more than 95% of the particles were blocked

U.S. government researchers found that two masks are better than one in slowing coronavirus spread, but health officials stopped short of recommending that everyone double up.

The Centers for Disease Control and Prevention on Wednesday reported the results of a lab experiment that spaced two artificial heads 6 feet from each other and checked to see how many coronavirus-sized particles spewed by one were inhaled by the other.

The researchers found that wearing one mask — surgical or cloth — blocked around 40% of the particles coming toward the head that was breathing in. When a cloth mask was worn on top of a surgical mask, about 80% were blocked.

When both the exhaling and inhaling heads were double-masked, more than 95% of the particles were blocked, said the CDC’s Dr. John Brooks.

Still, for now, health authorities acknowledge they have their hands full just trying to get more people to wear one mask and wear it correctly.

“The first challenge is to get as many as people as possible masking. And then for those that do mask, to help them get the best benefit out of that mask,” Brooks said.

Brooks said agency officials heard about people donning two masks and wanted to evaluate whether it was beneficial.

The study had many limitations: The researchers used one brand of surgical mask and one kind of cloth mask, and it’s not clear if results would be the same with every product. But it echoes some earlier research that suggests two masks are better than one.

“It works,” Brooks said.

The CDC updated its guidance, saying people can wear a cloth mask on top of a disposable surgical mask “for better fit and extra protection.” If done correctly, the combination can tighten the gaps around the mask’s edges that can let virus particles in, the CDC said.

The agency also said it will take down a make-your-own mask page, which went up last year when masks were in short supply and the CDC was encouraging people to take steps to interrupt viral transmission.

Some Americans have already started doubling up. Experts believe that’s at least partly out of concern about new strains of coronavirus that have been found to spread more easily than the one that has driven the U.S. epidemic for the past year

CDC guidance has evolved over the course of the epidemic.

Mask-wearing has long been common in some countries during respiratory outbreaks, especially in parts of Asia, but not in the United States.

When the COVID-19 crisis began and masks disappeared from store shelves, U.S. health officials actively discouraged the general public from wearing them. “Seriously people – STOP BUYING MASKS!” then-Surgeon General Jerome Adams wrote in a tweet almost a year ago.

Two months later, after it became clear that infected people who did not exhibit symptoms could spread the virus, the CDC began recommending people wear masks in public.

READ MORE: Threat from variants means provinces must be ready to lock down again quickly: Tam

Mask-wearing increased and some places enforced mask mandates, but many Americans continue not to wear them. A recent University of California survey suggested that only about half of U.S. adults wear masks when in close contact with people outside their household.

Discussions about double-masking and higher-quality masks are important, said Dr. Isaac Bogoch, an infectious diseases scientist at the University of Toronto.

“But if a significant proportion of your populations isn’t wearing a mask in the first place, then you’re having the wrong conversation,” he added.

___

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.

Mike Stobbe, The Associated Press


Like us on Facebook and follow us on Twitter.

Want to support local journalism during the pandemic? Make a donation here.

Coronavirus

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Allison O’Neil. (Phil McLachlan, Kelowna Capital News)
Okanagan College prof encourages women to excel in math and science

Allison O’Neil is works in the engineering department at the Kelowna campus

The Great Bear Snowshed on the Coquihalla Highway (Highway 5) in British Columbia. Truck driver Roy McCormack testified in BC Supreme Court in Chilliwack on Feb. 25, 2021 that his brakes started smoking in about this location, and soon after he lost all braking, which led to a multi-vehicle crash further down the road on Aug. 5, 2016. (GoogleMaps)
Truck driver charged in Coquihalla crash showed ‘wanton and reckless disregard for other people’s lives’: Crown

Despite already having brake issues, Roy McCormack tackled the steepest hill on the infamous highway

A health worker holds a vial of AstraZeneca vaccine to be administered to members of the police at a COVID-19 vaccination center in Mainz, Germany, Thursday, Feb. 25, 2021. The federal state of Rhineland-Palatinate, start with the vaccination of police officers in internal police vaccination centers. (Andreas Arnold/dpa via AP)
B.C. officials to unveil new details of COVID vaccination plan Monday

Seniors and health-care workers who haven’t gotten their shot are next on the list

An investigation is underway after a man was shot and killed by Tofino RCMP in Opitsaht. (Black Press Media file photo)
Man shot and killed by RCMP near Tofino, police watchdog investigating

Investigation underway by Independent Investigations Office of British Columbia.

B.C. Supreme Court in Vancouver on Tuesday December 11, 2018. THE CANADIAN PRESS/Darryl Dyck
B.C.’s compromise on in-person worship at three churches called ‘absolutely unacceptable’

Would allow outdoor services of 25 or less by Langley, Abbotsford and Chilliwack churches

Wills Hodgkinson, 10, and his mom Neeley Brimer get ready to battle round three of cancer. The community of Penticton has his back. (Submitted)
Community raises $21K to help Penticton boy battle third round of cancer

Okanoggin Barbers held the fundraiser on Saturday for 10-year-old Wills Hodgkinson

Baldy Mountain Resort was shut down on Saturday after a fatal workplace accident. (Baldy Mountain picture)
UPDATE: 70-year-old man killed in workplace accident at Baldy Mountain

The mountain closed on Saturday but has partially re-opened today (Sunday)

Jasmine and Gwen Donaldson are part of the CAT team working to reduce stigma for marginalized groups in Campbell River. Photo by Marc Kitteringham, Campbell River Mirror
Jasmine’s story: Stigma can be the hardest hurdle for those overcoming addiction

Recovering B.C. addict says welcome, connection and community key for rebuilding after drug habit

Chase RCMP held two men involved in drunken disturbances overnight in their detachment’s cells on Feb. 6. (File Photo)
Chase RCMP hold two men involved in drunken disturbances overnight

The two separate incidents took place less than an hour apart.

Cannabis bought in British Columbia (Ashley Wadhwani/Black Press Media)
Is it time to start thinking about greener ways to package cannabis?

Packaging suppliers are still figuring eco-friendly and affordable packaging options that fit the mandates of Cannabis Regulations

Kamloops Fire Rescue battled a landfill fire which belched toxic smoke into the air on Feb. 27. (City of Kamloops Photo)
Fire at Kamloops landfill sends thick black smoke into the air

Firefighters made slow progress on the fire throughout the morning.

Most Read