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

Amanda Parsons, a registered nurse on staff at the Northwood Care facility, prepares a dose of the Moderna vaccine in Halifax on Monday, Jan. 11, 2021. Almost two in three Canadians surveyed recently said they trust COVID-19 vaccines to be both safe and effective. THE CANADIAN PRESS/Andrew Vaughan
Northern Health to open 30 COVID vaccine clinics for oldest residents, Indigenous seniors

Health authority says it plans to vaccinate nearly 15,000 people in Phase Two

Prince Rupert’s Bobby Brown celebrated his 95th birthday milestone on March 5 with family across the country in an online celebration. (Photo: supplied by Jodi Brown)
Prince Rupert man celebrates 95th birthday milestone online

Five generations come together COVID-19 style in Prince Rupert to say “Happy Birthday”

Main door at Cranes Crossing, Prince Rupert’s homeless shelter, on March 5. Northern Health issued a public notice of potential exposure occurring at the shelter between Feb. 22 and 24. (Photo: K-J Millar/The Northern View)
COVID-19 Public Exposure Notice issued for Prince Rupert’s homeless shelter

Northern Health said possible exposure between Feb. 22 and 24

Air Canada cancelled flights to Prince Regional Airport on Jan. 23, 2021 due to loss of ridership during COVID-19. An Air Canada Rouge takes off from Montreal in March 20, 2020. (THE CANADIAN PRESS/Graham Hughes)
BC Liberals call for immediate action and support for B.C. airports

Prince Rupert Regional Airport and others across the province struggle with COVID-19 effects

Paul Williams rector of St. Andrews Cathedral in Prince Rupert sits in front of the 95-year-old pipe organ on March 5. The church has put out a community call for volunteers to play the instrument to keep it fresh and operational. (Photo: K-J Millar/The Northern View)
St. Andrews Cathedral pipe organ needs players to make it sing

Prince Rupert volunteers who want to practice their playing skills are welcome

Elvira D’Angelo, 92, waits to receive her COVID-19 vaccination shot at a clinic in Montreal, Sunday, March 7, 2021, as the COVID-19 pandemic continues in Canada and around the world. THE CANADIAN PRESS/Graham Hughes
‘It’s been a good week’: Tam hopeful on vaccines as pandemic anniversary nears

Tam says the addition of two new vaccines will help Canadians get immunized faster

Const. Allan Young. Photo: Abbotsford Police Department
Manslaughter charge laid in Nelson death of Abbotsford police officer

Allan Young died after an incident in downtown Nelson last summer

(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

Pictures and notes in from friends and classmates make up a memorial in support and memory of Aubrey Berry, 4, and her sister Chloe, 6, during a vigil held at Willows Beach in Oak Bay, B.C., on December 30, 2017. THE CANADIAN PRESS/Chad Hipolito
Mother of slain daughters supports recent changes to Canada’s Divorce Act

Sarah Cotton-Elliott said she believed her children took a back seat to arranging equal parenting

Victoria man Brett Andersen is asking for people’s help to secure him one of eight free tickets to the moon. (Screenshot/@brettandersen Instagram)
Victoria man wants your help securing a free ticket to the moon

Japanese billionaire offering eight people a trip to the moon

The Conservation Officers Service is warning aquarium users after invasive and potentially destructive mussels were found in moss balls from a pet store. (BC Conservation Officers Service/Facebook)
Aquarium users in B.C. warned after invasive mussels found at pet store

Conservation officers were told the mussels were found in a moss ball from a Terrace pet store.

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

Donald Alan Sweet was once an all star CFL kicker who played for the Montreal Alouettes and Montreal Concordes over a 13-year career. Photo courtesy of Mission RCMP.
Ex-B.C. teacher who was CFL kicker charged with assault, sexual crimes against former students

Donald Sweet taught in Mission School District for 10 years, investigators seek further witnesses

Most Read