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

Just Posted

Patrons rip around a corner on the go-kart course at Lakeshore Go-Karts and Mini-Golf. (Photo by Megan Roth/Sylvan Lake News)
Sylvan Lake go-kart and mini golf course reopens after fire

Last August the outdoor facility was shut down after a fire burned through much of the business

(File photo from The Canadian Press)
Red Deer down to 66 active COVID-19 cases

Red Deer has lowest number of active cases since last November

A small selection of shoes line a step at the Municipal Government Building in Sylvan Lake, with each pair representing a vicitm of residential schools in Canada. Tracey Greinke placed the first pair of shoes on the steps, hoping more would follow. (Photo by Megan Roth/Sylvan Lake News)
Sylvan Lake woman sets up small memorial for residential school victims

Tracey Grienke placed a pair of moccasins on the steps of town hall, and a few more followed

FILE – Perry Bellegarde, National Chief of the Assembly of First Nations, takes part in an event on Parliament Hill in Ottawa on Tuesday, July 7, 2020. THE CANADIAN PRESS/Sean Kilpatrick
Indigenous Peoples Day must be a ‘call to action’, says Assembly of First Nations chief

Discovery of children at Kamloops residential school site must lead to change, Perry Bellegarde says

Left handed pitcher Evan Wilde started the game for Sylvan Lake and allowed four runs in the 12-10 extra-innings loss against the Edmonton Prospects on Sunday in Western Canadian Baseball League play. (Photos by Byron Hacket/Blakc Press News Media)
Historic opening weekend for Sylvan Lake Gulls

The Gulls finished the opening weekend with one win and two losses

The border crossing into the United States is seen during the COVID-19 pandemic in Lacolle, Que. on February 12, 2021. THE CANADIAN PRESS/Paul Chiasson
VIDEO: Border quarantine to soon lift for fully vaccinated Canadians

Eligible travellers must still take multiple COVID-19 tests

Fans watch the warm-up before Game 6 between the Toronto Maple Leafs and the Montreal Canadiens in NHL playoff hockey action Saturday, May 29, 2021 in Montreal. Quebec’s easing of COVID-19 restrictions will allow 2,500 fans to attend the game for the first time in fourteen months. THE CANADIAN PRESS/Ryan Remiorz
Two-thirds of Canadians say governments shouldn’t lift all COVID-19 restrictions

Poll reports Canadians who gained pandemic weight say they have gained 16 pounds on average

Paul Bernardo is shown in this courtroom sketch during Ontario court proceedings via video link in Napanee, Ont., on October 5, 2018. Teen killer and serial rapist Paul Bernardo is set for a parole hearing today. The designated dangerous offender, has been eligible for full parole for more than three years. Bernardo’s horrific crimes in the 1980s and early 1990s include for kidnapping, torturing and killing Kristen French and Leslie Mahaffy near St. Catharines, Ont. THE CANADIAN PRESS/Greg Banning
Killer rapist Paul Bernardo faces parole hearing today; victim families opposed

Designated dangerous offender has been eligible for full parole for more than three years.

People look over the damage after a tornado touched down in Mascouche, Que., north of Montreal, Monday, June 21, 2021. Dozens of homes were damaged and one death has been confirmed. THE CANADIAN PRESS/Ryan Remiorz
One dead and extensive damage as tornado hits Mascouche, Que., north of Montreal

Damage reported in several parts of the city, and emergency teams dispatched to sectors hardest hit

FILE - In this Nov. 29, 2020, file photo, Las Vegas Raiders defensive end Carl Nassib leaves the field after an NFL football game against the Atlanta Falcons in Atlanta. Nassib on Monday, June 21, 2021, became the first active NFL player to come out as gay. Nassib announced the news on Instagram, saying he was not doing it for the attention but because “I just think that representation and visibility are so important.” (AP Photo/John Bazemore, File)
Nassib becomes first active NFL player to come out as gay

More than a dozen NFL players have come out as gay after their careers were over

A pair of Alberta residents were arrested after police responded to a report of a woman who had allegedly been assaulted and confined against her will on June 20, 2021. (File photo)
Salmon Arm RCMP arrest 2 Albertans suspected in alleged assault, unlawful confinement

Firearms, stolen items seized including NHL hockey cards believed to be worth thousands

A man makes his way past signage to a mass COVID-19 vaccination centre at the University of Toronto’s Mississauga campus during the COVID-19 pandemic in Mississauga, Ont., on Monday, May 17, 2021. THE CANADIAN PRESS/Nathan Denette
Canadians encouraged to see mRNA shots as interchangeable as more 2nd doses open up

Doctors urge people not to hesitate if offered Moderna after getting Pfizer for their first shot

Chief of Defence Staff Jonathan Vance sits in the front row during a news conference in Ottawa on June 26, 2020. THE CANADIAN PRESS/Adrian Wyld
Defence committee rises without report on Vance allegations

Committee had been investigating the government’s handling of complaints against former defence chief

Tl’etinqox-lead ceremony at the site of the former St. Joseph’s Mission in Williams Lake, B.C., June 18, 2021. (Angie Mindus photo - Williams Lake Tribune)
‘We are all one people’: Honouring residential school victims and survivors

Love, support and curiousity: Canadians urged to learn about residential schools and their impact

Most Read