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

A health care worker prepares to test a Coastal GasLink field worker for COVID-19. (Coastal GasLink photo)
Coastal GasLink begins COVID screening of pipeline workers

Construction is once again ramping up following Northern Health approval of COVID management plan

FILE – A COVID-19 vaccine being prepared. (Olivia Sullivan/Sound Publishing)
B.C. seniors 80 years and older to get COVID vaccine details over next 2 weeks: Henry

Province is expanding vaccine workforce as officials ramp up age-based rollout

Chris Paulson of Burns Lake took a quick selfie with a lynx over the weekend of Feb. 20-22, 2021, after the wild cat was found eating some of his chickens. (Chris Paulson/Facebook)
VIDEO: Burns Lake man grabs lynx by scruff after chickens attacked

‘Let’s see the damage you did, buddy,’ Chris Paulson says to the wild cat

Northern Health has declared a COVID-19 outbreak at Brucejack mine, 65 km north of Stewart on Feb. 11, 2021. (Pretivm Photo)
Northern Health has declared a COVID-19 outbreak at Brucejack Mine, 65 kilometres north of Stewart on Feb. 11, 2021. (Pretivm Photo)
Northern Health reports 20 more COVID-19 cases in outbreak at Brucejack Mine

So far, 42 people have tested positive, nine cases are active and self-isolating onsite

Abbotsford’s Kris Collins turned to TikTok out of boredom when the provincial COVID-19 lockdown began in March 2020. She now has over 23 million followers on the video app. Photo: Submitted
Internet famous: Abbotsford’s Kris Collins is a TikTok comedy queen

Collins has found surprise stardom alone with a phone

Nanaimo children’s author and illustrator Lindsay Ford’s latest book is ‘Science Girl.’ (Photo courtesy Lindsay Ford)
B.C. children’s writer encourages girls to pursue the sciences in new book

Lindsay Ford is holding a virtual launch for latest book, ‘Science Girl’

Pig races at the 145th annual Chilliwack Fair on Aug. 12, 2017. Monday, March 1, 2021 is Pig Day. (Jenna Hauck/ Chilliwack Progress file)
Unofficial holidays: Here’s what people are celebrating for the week of Feb. 28 to March 6

Pig Day, Canadian Bacon Day and Grammar Day are all coming up this week

Staff from the Marine Mammal Rescue Centre, passersby, RCMP and Nanaimo Fire Rescue carried a sick 300-kilogram steller sea lion up the steep bluff at Invermere Beach in north Nanaimo in an attempt to save the animal’s life Thursday. (Photo courtesy Marine Mammal Rescue Centre)
300-kilogram sea lion muscled up from B.C. beach in rescue attempt

Animal dies despite efforts of Nanaimo marine mammal rescue team, emergency personnel and bystanders

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

Doctors and counsellors warn of an increase in panic attacks, anxiety, depression and suicide ideas between ages 10 to 14, in Campbell River. ( Black Press file photo)
Extended pandemic feeding the anxieties of B.C.’s youth

Parents not sure what to do, urged to reach out for help

Kara Sorensen, diagnosed with lung cancer in July, says it’s important for people to view her as healthy and vibrant, rather than sick. (Photo courtesy of Karen Sorensen)
B.C. woman must seek treatment overseas for inoperable lung cancer

Fundraising page launched on Karen Sorensen’s behalf, with a goal of $250,000

Gina Adams as she works on her latest piece titled ‘Undying Love’. (Submitted photo)
‘Toothless’ the kitty inspires B.C. wood carver to break out the chainsaw

Inspired by plight of a toothless cat, Gina Adams offers proceeds from her artwork to help animals

B.C. Finance Minister Selina Robinson presents bill to delay B.C.’s budget as late as April 30, and allow further spending before that, B.C. legislature, Dec. 8, 2020. (Hansard TV)
How big is B.C.’s COVID-19 deficit? We’ll find out April 20

More borrowing expected as pandemic enters second year

Most Read