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

(Photo from Highway 11 Functional Planning Study)
Public input wanted for Highway 11 improvement plan

Round 2 of public online engagement continues until March 10

File photo
Gov’t of Alberta identifies estimated 300 new COVID-19 cases Sunday

Online COVID-19 dashboard unavailable as upgrades being completed

COVID
Red Deer down to 313 active cases of COVID-19

Alberta reports an additional 411 COVID-19 cases

Seniors in the 65-unit Piper Creek Lodge are among those waiting for COVID-19 vaccinations. (File photo by Advocate staff)
Central Alberta senior lodges anxiously waiting for COVID-19 vaccinations

“Should be at the front of the line, not the back of the line”

(The Canadian Press)
‘Worse than Sept. 11, SARS and financial crisis combined’: Tourism industry in crisis

Travel services saw the biggest drop in active businesses with 31 per cent fewer firms operating

David and Collet Stephan leave for a break during their appeal hearing in Calgary on Thursday, March 9, 2017. THE CANADIAN PRESS/Todd Korol
Alberta Appeal Court orders 3rd trial for parents in toddler’s meningitis death

Stephans were accused of not seeking medical attention sooner for Ezekiel, who had meningitis when he died

A health-care worker prepares a dose of the Pfizer-BioNTech COVID-19 vaccine at a UHN COVID-19 vaccine clinic in Toronto on Thursday, January 7, 2021. THE CANADIAN PRESS/Nathan Denette
Vaccine hesitancy decreases in B.C. as mass immunizations set to begin: poll

Two-thirds of British Columbians, and Canadians, would get the vaccine as soon as possible

A woman walks through Toronto’s financial district on Monday, July 30, 2018. A new poll suggests most Canadians believe there’s still a long way to go to achieve gender equality in this country. THE CANADIAN PRESS/Graeme Roy
Canadians, especially women, say gender equality not achieved in Canada: Poll

Poll results themselves underscore the challenge, with more men believing equality had been achieved

This image provided by Harpo Productions shows Meghan, The Duchess of Sussex, left, in conversation with Oprah Winfrey. (Joe Pugliese/Harpo Productions via AP)
Race, title and anguish: Meghan and Harry explain royal rift

Meghan said she struggled with concerns within the royal family about her son’s skin colour

Kiara Robillard is seen in an undated handout photo. When the pandemic began, Robillard had to rush back home to Alberta from California, where she had been living for five years, after she was struck by a truck that broke her spine in two places. THE CANADIAN PRESS/HO-Kiara Robillard, *MANDATORY CREDIT*
‘It kind of clicks:’ Text4Hope program helps with depression, anxiety during pandemic

Participants receive one text message every morning for three months

Hockey hall-of-fame legend Wayne Gretzky, right, watches the casket of his father, Walter Gretzky, as it is carried from the church during a funeral service in Brantford, Ont., Saturday, March 6, 2021. HE CANADIAN PRESS/Nathan Denette
Walter Gretzky remembered as a man with a ‘heart of gold’ at funeral

The famous hockey father died Thursday at age 82 after battling Parkinson’s disease

Supporters rally outside court as Pastor James Coates of GraceLife Church is in court to appeal bail conditions, after he was arrested for holding day services in violation of COVID-19 rules, in Edmonton, Alta., on Thursday March 4, 2021. THE CANADIAN PRESS/Jason Franson
‘Law remains valid:’ Pastor accused of violating health orders to remain in jail

The Justice Centre for Constitutional Freedoms is representing the pastor

A decommissioned pumpjack is shown at a well head on an oil and gas installation near Cremona, Alta., Saturday, Oct. 29, 2016. The Alberta Energy Regulator says it is suspending all of the licences held by an oil and gas producer with more than 2,200 wells and 2,100 pipelines after it failed to bring its operations into compliance. THE CANADIAN PRESS/Jeff McIntosh
Alberta Energy Regulator suspends licences of oil and gas producer that owes $67M

The company is being asked to comply with past orders to clean up historic spills and contamination

Most Read