Masks for COVID-19 are effective

Jan Brostek, owner of Pins and Needles, sews a mask for distribution to local hospitals on March 25, 2020, in Middleburgh Heights, Ohio. (AP)

A Facebook user declared, “I’m starting a public movement called TAKE IT OFF,” in attempting a six-point takedown of facial coverings and how effective they are in fighting COVID-19.

The post features an image labeled “Face Mask Safety — Know The Facts Before You Wear One.” The image makes this six-part claim about masks:

“Decreases oxygen intake; increases toxin inhalation; shuts down immune system; increases virus risk; scientifically inaccurate; effectiveness not studied.”

The post was flagged as part of Facebook’s efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Facebook.)

“Well, that all sounds like a lot of dangerous nonsense,” Texas A&M University-Texarkana virologist Ben Neuman told PolitiFact.

As we’ve reported, facial coverings are not in themselves totally effective in fighting the coronavirus and there is a need for more study. But health officials largely agree that wearing any kind of face mask, coupled with social distancing and frequent hand-washing, is more protective than going unmasked.

While the U.S. Centers for Disease Control and Prevention doesn’t recommend masks for children under age 2 or for people who are unconscious or have breathing conditions, it generally recommends wearing masks in public settings where other social distancing measures are difficult to maintain, such as grocery stores, pharmacies, and gas stations. As the CDC puts it: “Your cloth face covering may protect them. Their cloth face covering may protect you.”

Here’s a rundown on why each part of the post is wrong.

“Breathing through a mask decreases the amount of oxygen we need to live & be healthy, increases blood acidity & makes breathing difficult.”

A mask does not reduce oxygen intake nor does it make blood more acidic, virologist Angela Rasmussen, a research scientist at Columbia University, told PolitiFact.

Neuman said a mask “will add some resistance to the breathing process, meaning it may feel like it takes a bit more work to take a breath, but it won’t materially change the makeup of air that comes through the mask.”

“Toxins that we normally exhale as we breathe become trapped in the mask and re-inhaled into the lungs, increasing symptoms.”

Repeated, long-term usage of the same unwashed mask could potentially lead to bacteria accumulating on the inside, which is why paper masks shouldn’t be reused and cloth masks should be laundered with soap between uses, Rasmussen said. “However, there’s no reason to worry about ‘toxins,’’ she said. “The only potentially toxic molecule that you routinely exhale is carbon dioxide, which is only toxic when it displaces oxygen,” and it easily passes through the mask.

Neuman also said carbon dioxide would not be trapped by a mask.

“Decreases oxygen intake, increases carbon dioxide & toxin intake putting body under stress, releasing cortisol & shutting down immune processes.”

Not true.

“There’s no decreased oxygen or increased carbon dioxide from normal breathing while wearing a mask, and no evidence that masks have any effect on the immune system or immune function,” Rasmussen said.

Inhaling high levels of carbon dioxide is dangerous, but this is very unlikely to happen from wearing a cloth face mask — especially if you’re only wearing it for short periods of time, according to the Cleveland Clinic.

There are studies that show that medical N95 respirators may result in increased carbon dioxide, which can lead to headaches and fatigue. This is one reason they’re not recommended for home use,” University of San Francisco research scientist Jeremy Howard told PolitiFact. “Cloth masks, on the other hand, have excellent breathability and the same problems have not been demonstrated with them.”

A USA Today fact-check said a similar claim, that masks weaken the immune system, was false.

“Encourages triggering & infection from dormant retro viruses already in the body, taking advantage of a weakened immune system due to mask wearing.”

Masks can be effective in preventing the spread of COVID-19 because COVID-19 spreads mainly from person to person through respiratory droplets produced when an infected person coughs, sneezes, or talks, according to the CDC. The droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs.

“It’s absurd to think that masks would ‘trigger’ their activation and cause disease, especially since mask-wearing has no effect on immune system function,” Rasmussen said.

“Virologists measure COVID-19 to be 80-140nm in size making the weave of material masks to be the equivalent of a chain-link fence to a mosquito.”

(NM is a reference to the nanometer measure of diameter.)

Rasmussen said virus particles are much smaller than the weave of masks, but infected people do not shed individual virus particles into the environment — they shed them in respiratory droplets. Masks prevent most, but not all, of these respiratory droplets from being dispersed into the environment.

“In addition, although we don’t know how many virus particles it takes to cause an infection, it’s almost certainly more than one. So you have to be exposed to enough respiratory droplets containing enough virus to establish an infection to actually become infected. Reducing droplet dispersal by wearing a mask greatly reduces this exposure risk, though it does not eliminate it completely,” she said.

Neuman said there is a growing number of research papers that demonstrate the effectiveness of surgical face masks in preventing transmission of a range of viruses, or demonstrate the effectiveness of face covering in limiting the novel coronavirus spread.

“Absolutely no peer-reviewed studies have been carried out of mask effectiveness within a social environment to control, prevent or eliminate the spread of disease.”

Both papers cited by Neuman are published and peer reviewed. One was published in April by the journal Nature and the other on June 11 by the National Academy of Sciences. In terms of being “within a social environment,” 246 individuals provided exhaled breath samples in the first study, roughly half with masks and half without; the second study was a review of coronavirus mitigation efforts undertaken in Wuhan, China, Italy and New York City.

Said Rasmussen: “It’s true that to my knowledge masks have not been subjected to a large, randomized clinical trial, but a growing body of evidence does suggest that masks substantially reduce droplet spread.”

A Facebook post claimed that wearing masks for the coronavirus “decreases oxygen intake, increases toxin inhalation, shuts down immune system, increases virus risk, scientifically inaccurate, effectiveness not studied.”

There is no evidence to back any of the six parts of the claim.

We rate it False.