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Normal use of face masks do not cause pneumonia

June 24, 2020 GMT

CLAIM: Wearing face masks can cause fungal and bacterial pneumonia. 

AP’S ASSESSMENT: False. There’s no evidence that normal use of face masks can cause fungal or bacterial infections. 

THE FACTS: A false post about wearing face masks has been circulating widely on Twitter after it was tweeted on June 19 by a congressional candidate in Florida.

“Excessive use of face masks causes fungal and bacterial pneumonia,” wrote Jessi Melton, a conservative business owner running to represent Florida’s 22nd Congressional District. The false post had over 16,000 retweets as of Wednesday. 


“There’s no evidence of masks leading to fungal or bacterial infections of the upper airway or the lower airway as in pneumonia,” said Davidson Hamer, infectious disease specialist and professor of global health and medicine at Boston University. 

Hamer noted that bacterial growth could occur, in theory, if someone wore a mask that was already contaminated with moisture and became moldy. “I don’t know why anybody would do that. Theoretically, it could happen, but it’s highly unlikely with just typical mask use,” he said in a phone call with The Associated Press. 

There’s no evidence that wearing face masks cause any harm besides some discomfort, Hamer said. However, he added paper masks that become visibly wet should be discarded. 

Anne Monroe, an internal medicine physician and epidemiologist at George Washington University’s Milken Institute School of Public Health, agreed: “There’s no evidence to back up this claim. Digging into it a little bit more, in terms of mask use, it is important to follow general sanitation guidelines.” 

Monroe said it’s important that disposable masks be discarded and cloth masks be washed. “The idea that contamination could cause fungal pneumonia is not a valid conclusion,” she said in a phone interview with the AP. Monroe agreed with Hamer that it’s “potentially theoretical,” but that it has not been documented. 

“It’s so highly unlikely with normal mask use,” Hamer explained. “There’s a real danger at spreading incorrect information like this, especially at a time when we really need to be encouraging more people to wear masks,” he added. 


During the COVID-19 pandemic, there have been other false claims about wearing masks. One that circulated widely falsely stated that wearing face masks for long periods of time could cause hypercapnia, a situation where there is too much carbon dioxide in the bloodstream. Mild cases can lead to issues such as headache and anxiety; severe cases can interfere with breathing.


This is part of The Associated Press’ ongoing effort to fact-check misinformation that is shared widely online, including work with Facebook to identify and reduce the circulation of false stories on the platform.

Here’s more information on Facebook’s fact-checking program: