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

B.C. RCMP Lower Mainland District officer, Asst. Commissioner Stephen Thatcher presents RCMP blankets to (from left) Chief James Hobart, Chief Maureen Chapman, Chief Derek Epp and Chief Mark Point. (RCMP)
14 Fraser Valley Indigenous communities finalize agreement with RCMP for more safety, services

Community Safety Agreement builds relationship of ‘trust, communication and prevention,’ says Chief

Canadian Reformed Church in Chilliwack. (GoogleMaps)
OPINION: Churches that defy the law and public health orders are in the extreme minority

The nature of news coverage means that aberrations from the norm are what make the headlines

Projects recently approved by council will tackle homelessness in Chilliwack. (Black Press file photo)
Latest projects taking on homelessness in Chilliwack focused on pandemic pivoting

4 key service providers will share a blended fund of almost $160,000 in Reaching Home funding

Free Reformed Church is seen as people attend service, in Chilliwack, B.C., on Sunday, Feb. 21, 2021. Lawyers for the British Columbia government and the Justice Centre for Constitutional Freedoms are back in B.C. Supreme Court today, squaring off over the legality of COVID-19 rules that prohibit in-person religious services. THE CANADIAN PRESS/Darryl Dyck
B.C. top doctor has power to restrict access to a place during health hazard: lawyer

Under B.C.’s Public Health Act, Jacqueline Hughes says, Henry can restrict or prevent entry to a place

These free, postage-paid postcards were sent to 13.5 million households across Canada. (Jennifer Feinberg/ The Chilliwack Progress)
OPINION: Singing the praises of these postcards of positivity

I typed this ode to the loveliness of hand-written notes on a computer but the point still stands

The James C Richardson Pipe Band marches in a Remembrance Day parade on Nov. 11, 2019 in Chilliwack. Wednesday, March 10 is International Bagpipe Day. (Jenna Hauck/ Chilliwack Progress file)
Unofficial holidays: Here’s what people are celebrating for the week of March 7 to 13

International Bagpipe Day, Wash Your Nose Day and Kidney Day are all coming up this week

More than ever before, as pandemic conditions persist, the threat of data breaches and cyberattacks continues to grow, according to SFU professor Michael Parent. (Pixabay photo)
SFU expert unveils 5 ways the COVID-19 pandemic has forever changed cybersecurity

Recognizing these changes is the first in a series of steps to mitigate them once the pandemic ends, and before the next: Michael Parent

The driver of a pickup truck failed to stop after knocking down a wooden fence on March 3, 2021. (screen grab)
VIDEO: Footage catches pick-up driver smash fence on Abbotsford/Langley border

Driver came forward after video circulated on social media

Lower Mainland teens with Ocean Wise’s YouthToSea program have launched an initiative called Clean Coastal, Eat Local, through which they’re offering restaurant gift cards to individuals or households that organize a coastal cleanup in the month of March. (Photo supplied by Ocean Wise)
Teens challenge Lower Mainlanders to clean up their act

YouthToSea offers restaurant gift cards in exchange for a cleaner coastline

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

Kevin Haughton is the founder/technologist of Courtenay-based Clearflo Solutions. Scott Stanfield photo
Islander aims Clearflo clean drinking water system at Canada’s remote communities

Entrepreneur $300,000 mobile system can produce 50,000 litres of water in a day, via solar energy

Malawian police guard AstraZeneca COVID-19 vaccines after the shipment arrived in Lilongwe, Malawi, Friday March 5, 2021. Canada is expecting its first shipments of AstraZeneca vaccine next week. (Associated Press/Thoko Chikondi)
B.C.’s daily COVID-19 cases climb to 634 Friday, four more deaths

Currently 255 people in hospital, 66 in intensive care

A crashed helicopter is seen near Mt. Gardner on Bowen Island on Friday March 5, 2021. Two people were taken to hospital in serious but stable condition after the crash. (Irene Paulus/contributed)
2 people in serious condition after helicopter goes down on Bowen Island

Unclear how many passengers aboard and unclear where the helicopter was going

Surrey Pretrial in Newton. (Photo: Tom Zytaruk)
B.C. transgender inmate to get human rights hearing after being held in mostly male jail

B.C. Human Rights Tribunal member Amber Prince on March 3 dismissed the pretrial’s application to have Makayla Sandve’s complaint dismissed

Most Read