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

The Terrace & District Chamber of Commerce hosted a virtual all candidates forum for the Coast Mountains School District trustee by-election on Feb. 23, 2021. (Screenshot/Terrace & District Chamber of Commerce Facebook)
Terrace trustee candidates lay out top priorites during virual all candidates forum

All candidates forum was held virtually on Feb. 23, 2021

(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

(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 Majagaleehl Gali Aks Elementary School in Hazelton is being shut down for a week by the Gitanmaax Band Council following a confirmation of a COVID-19 exposure there on Feb. 26. (Black Press Media File Photo)
COVID-19 exposure notice shuts down Hazelton school

Closure to last for one week and school is to be sanitized

A health-care worker looks at a dose of the COVID-19 vaccine at the Palais de Congress site as Quebec begins mass vaccinations based on age across the province, Monday, March 1, 2021 in Montreal.THE CANADIAN PRESS/Ryan Remiorz
Nearly 1 million COVID-19 vaccine doses arriving in Canada this week: Anand

Anita Anand says she’s received assurances from the vaccine manufacturer

Kelowna’s lakefront visitor centre is one of 130 around the province. Tourism businesses have been hardest hit by COVID-19 restrictions on travel. (Destination B.C.)
Tourism, small business getting COVID-19 help, B.C. minister says

$300M grant program has delivered $50 million so far

The incident happened in downtown Castlegar. Photo: Betsy Kline
Castlegar teen recounts stabbing after stranger breaks into grandmother’s house

The unnamed teen survived a terrifying attack Feb. 21

(Black Press file photo)
Agassiz boy, 11, dies from ‘extensive injuries’: Homicide team

Agassiz RCMP were called out Friday to assist with a child in medical distress

Dr. Amit Desai of St. Francis Hospital receives a COVID-19 vaccine on Dec. 17. (Photo courtesy of CHI Franciscan)
B.C. has now vaccinated more people from COVID-19 than total confirmed cases

B.C. has reached a milestone, vaccinating roughly 1.6% of its population from the coronavirus

Nanaimo RCMP are looking for a suspect who smashed the window of an adult toy store and made off with more than $1,200 in merchandise. (File photo)
Vancouver Island sex shop out $1,200 in merchandise after suspect steals ‘colossal’ product

Suspect smashed window of Nanaimo store, cutting himself in the process

Riverside Calvary Church in Walnut Grove. (Langley Advance Times file)
B.C. is ‘stereotyping’ churches as riskier for COVID than other spaces, lawyer argues

Judge said that freedom of expression, religion are not at issue in the case

B.C. Premier Gordon Campbell gets acquainted with Tsawwassen First Nation Chief Kim Baird’s 10-month-old daughter Sophia, husband Steve and four-year-old Amy at the B.C. legislature before a ceremony to endorse the Tsawwassen Treaty, Oct. 15, 2007. (Sharon Tiffin/Black Press)
Indigenous consent comes first and last for B.C. industrial projects

Environment minister can still approve permits without consent

B.C.’s court of appeal in Vancouver. (File photo: Tom Zytaruk)
Kootenay man appeals 7-year conviction for New Year’s Eve kidnapping, beating

Brandon Coons, 27, was convicted on five charges, including assault with a weapon

Most Read