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

Jovin Walkus and Alayah Mack enjoy the Centennial Pool in summer 2020. (Geneva Walkus photo)
CCRD receives more funding for Centennial Pool project

The total funding for the project is now over $4 million

Provincial funding in the amount of $300,000 has been announced for the Cariboo Regional District’s plans to improve the Anahim Lake Airport runway. (CRD photo)
$300,000 provincial funding to fuel Anahim Lake Airport runway upgrade

The recovery grant is one of 38 announced to support jobs in rural communities

(Phil McLachlan/Capital News)
Murder charge laid in February 2020 stabbing death of Smithers man

Michael Egenolf is charged with the second-degree murder of Brodie Cumiskey

Island Health chief medical officer Dr. Richard Stanwick receives a first dose of Pfizer vaccine, Dec. 22, 2020. (B.C. government)
COVID-19: B.C. seniors aged 90+ can start to sign up for vaccination on March 8

Long-term care residents protected by shots already given

The school is very proud of these students (pictured, left to right): Halim Demir (holding Grace Valdez’ gold certificate); Lauren McIlwain, Shayleen Mack, Jaymen Schieck, Kyle Doiron, and Finn Carlson (photo submitted)
SAMS students excel in international competition

The SAMS team swept their category this year; all six participants received awards

B.C. Health Minister Adrian Dix and provincial health officer Dr. Bonnie Henry head for the B.C. legislature press theatre to give a daily update on the COVID-19 pandemic, April 6, 2020. (B.C. government)
B.C. nears 300,000 COVID-19 vaccinations, essential workers next

564 new cases, four deaths, no new outbreaks Thursday

Walter Gretzky father of hockey hall-of-famer Wayne Gretzky waves to fans as the Buffalo Sabres play against the Toronto Maple Leafs during third period NHL hockey action in Toronto on Tuesday, Jan. 17, 2017. THE CANADIAN PRESS/Nathan Denette
Walter Gretzky, father of the Great One, dies at 82

Canada’s hockey dad had battled Parkinson’s disease and other health issues

Municipal Affairs Minister Josie Osborne speaks in the B.C. legislature, March 4, 2021. (Hansard TV)
B.C. Liberals, NDP sing in harmony on local election reforms

Bill regulates paid canvassers, allows people in condo buildings

(National Emergency Management Agency)
No tsunami risk to B.C. from powerful New Zealand earthquake: officials

An 8.1 magnitude earthquake shook the north of New Zealand Thursday morning

(AP Photo/Richard Vogel, File)
Pandemic stress, isolation key factors as to why Canadians turned to cannabis, alcohol

Study found that isolation played key role in Canadians’ substance use

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

Grand Forks’ Gary Smith stands in front of his Church of the Flying Spaghetti Monster float. Photo: Submitted
Grand Forks’ Flying Spaghetti Monster leader still boiling over driver’s licence photo

Gary Smith, head of the Church of the Flying Spaghetti Monster of B.C., said he has since spoken to lawyers

A Cowichan Valley mom is wondering why masks haven’t been mandated for elementary schools. (Metro Creative photo)
B.C. mom frustrated by lack of mask mandate for elementary students

“Do we want to wait until we end up like Fraser Health?”

Most Read