THE FACTS: Websites and social media users ranging from political candidates to health influencers are falsely claiming a study published on a digital research repository came from Stanford University and proves face masks are ineffective.

In reality, the study is not affiliated with Stanford, nor is the author.

The study is based on debunked claims about face masks, including the false notion that wearing a face covering decreases oxygen levels and increases carbon dioxide levels.

“Stanford peer review study on masks says they basically do not work for C-19,” the local North Dakota TV show POVNow posted on Facebook on Monday.

“A recent Stanford study released by the NCBI, which is under the National Institutes of Health, showed that masks do absolutely nothing to help prevent the spread of COVID-19 and their use is even harmful,” read a story on the conservative website The Gateway Pundit. The story was shared widely on Facebook and Twitter this week, including by Josh Mandel, a Republican U.S. Senate candidate in Ohio.

The study, titled “Facemasks in the COVID-19 era: A health hypothesis,” makes a variety of claims about negative health impacts of masks, including the false claim that wearing a face mask restricts breathing, leading to the conditions hypoxemia and hypercapnia.

Many doctors have taken to social media to debunk claims about oxygen levels and masks, and The Associated Press also has previously debunked false claims about health risks. The study also claims there is a lack of evidence for the effectiveness of face masks in preventing the spread of COVID-19.

In fact, a recent study added strong evidence that statewide mask mandates slow the spread of the coronavirus. Research shows masks block virus particles from spreading from infected people who wear them, and can even provide some protection to uninfected people who wear them.

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The study circulating online this week was first published in November in the journal “Medical Hypotheses,” which writes that its purpose is to “publish interesting theoretical papers.” Articles submitted to the journal are not meant to prove findings using primary data, but instead to advance hypotheses.

The journal has a “long history of publishing fringe science and hypotheses,” according to David Gorski, a surgical oncologist who blogs about medical misinformation.

The study’s author, Baruch Vainshelboim, is listed in the study as being affiliated with the cardiology division at the Veterans Affairs Palo Alto Health Care System/Stanford University. However, a representative for the VA Palo Alto Health Care System told the AP in an email that Vainshelboim does not work there.

“I can confirm this person is not one of our physicians,” wrote Michael Hill-Jackson, a public affairs specialist with the system. “I do not see him in our system and our Cardiology team has never heard of him.”

Vainshelboim also does not work for Stanford, according to Julie Greicius, senior director of external communications for the university’s medical school.

“Stanford University has never employed Baruch Vainshelboim,” Greicius wrote in an email to the AP. “Several years ago (2015), he was a visiting scholar at Stanford for a year, on matters unrelated to this paper.”

Vainshelboim, who lists himself on LinkedIn as a clinical exercise physiologist and does not list any current employment, did not respond to a request for comment.