There are many different types of face coverings being used during the COVID-19 pandemic.

Claims that face masks can cause illnesses are just hot air

AAP FactCheck July 3, 2020

The Statement

A widely-shared Facebook post claims that a grocery store worker who wore a mask for hours at a time got a lung infection from “breathing in her own bacteria”.

The post , which says it’s “from a friend,” claims to be originally from a parent whose healthy 19-year-old daughter was diagnosed with pleurisy, an inflammation of the lungs.

“They basically tell her … it’s because she has been wearing a mask for over 8 hours a day 5-6 days a week” during her work in a “huge grocery store chain,” the post states. “Breathing in her own bacteria. Carbon dioxide.. Caused an infection … But you wont (sic) see that on social media!”

There are several examples of the post shared by Australian and New Zealand users found here and here. In total they have received more than 60,000 views and more than 840 shares.

A Facebook post
 A Facebook post claims that a grocery store worker who wore a mask for hours got a lung infection. 

The Analysis

So can you actually get sick from breathing in your own air while wearing a face mask? The COVID-19 virus is primarily transmitted between people through respiratory droplets and contact routes, according to the World Health Organization. Airborne transmission differs from droplet transmission as it refers to the presence of microbes within droplet nuclei, WHO says. Respiratory droplets are between five to 10 micrometers in size and carbon dioxide molecules – and molecules in general – are far smaller than droplets.

Many papers have been written about the effectiveness of masks to prevent disease transmission. There are many different types of face coverings being used during the COVID-19 pandemic, ranging from home-made cloth coverings to medical-grade N95 filtered masks. Disposable surgical masks and cloth face masks are highly porous, allowing air to flow in and out while limiting the spread of droplets from coughing, sneezing and simply breathing. The Facebook post does not specify what kind of mask is referred to in the story.

You can catch the lung infection pleurisy via a virus such as the flu or a bacterial infection, such as pneumonia. However, if someone is exhaling viruses or bacteria, then they are already infected or “presymptomatic”, according to an article by science education website Health Feedback.

The Facebook post also claims that carbon dioxide caused an infection. There have been claims that wearing masks can cause hypercapnia, a build-up of carbon dioxide in the bloodstream. However, the World Health Organization says while the prolonged use of medical masks can be uncomfortable it does “not lead to CO2 intoxication nor oxygen deficiency”.

“While wearing a medical mask, make sure it fits properly and that it is tight enough to allow you to breathe normally,” WHO advises.

To address the post, AAP FactCheck sought the opinion of two experts: Dunedin pathologist Dr Ling Chan and epidemiologist, Professor Michael Baker, who is a member of New Zealand’s Ministry of Health’s COVID-19 Technical Advisory Group helping to co-ordinate the government’s response to the pandemic.

Dr Chan, a co-author on a recent New Zealand Medical Journal report on the use of masks in infection control, told AAP FactCheck there was no evidence that mask wearing increases carbon dioxide intake.

“The CO2 would pass through the gaps round the side and through the face covering as CO2 is much smaller than the fabric/mask materials,” she said.

“Tens of thousands of dentists, and health care professionals plus now millions of people around the world mask up for hours on end without an increase in rates of pneumonia.”

Prof Baker agreed that the claim did not “look plausible”.

Fact checks by the BBC and Poynter Institute examining the safety of wearing masks reached similar conclusions. A representative for the US Centers for Disease Control and Prevention told Reuters in May, “It is unlikely that wearing a mask will cause hypercapnia.”  The CDC does advise that children under two, and anyone who has trouble breathing should not use cloth face coverings.

The Verdict

Based on the evidence, AAP FactCheck finds the claims in the Facebook post to be false. Wearing a face mask for a prolonged period does not lead to CO2 intoxication nor oxygen deficiency, according to the World Health Organization. This conclusion was supported by a pathologist and an epidemiologist.

False – The primary claims of the content are factually inaccurate or misleading.

* AAP FactCheck is accredited by the Poynter Institute’s International Fact-Checking Network, which promotes best practice through a stringent and transparent Code of Principles.

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