No evidence that the use of a face mask causes lung cancer


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Social media posts and online articles claim that face masks recommended to stop the spread of Covid-19 cause lung cancer. But medical experts say there is no scientific evidence showing a direct link between long-term mask use and cancer.

Sorry, but you have lung cancer. But I don’t even smoke. But you’ve been wearing a mask for 8 months, ”says the text above an image of a woman speaking to a medical professional. The photo has been shared on Facebook on February 4, 2021.

Screenshot of a Facebook post taken on Feb 11, 2021

More examples of the post can be found here, here and here.

Since the start of the pandemic, misinformation about the use of masks has spread worldwide. The World Health Organisation, The United States. Center for Disease Control and Prevention and Health Canada agree masks are generally safe to use and help curb the spread of Covid-19 infected more than 100 million people, killing nearly 2.4 million people worldwide.

A similar claim can be found in one article Headed: “Long-term use of mask may contribute to advanced lung cancer, research shows.”

According to the social media monitoring tool CrowdTangle, it has been shared more than 3,400 times on Facebook. The article has also been published on – one site earlier fact-checked by AFP – and distributed Facebook and Instagram via screenshots of the same headline

Screenshot of an article taken on February 11, 2021

AFP also found that the claim was circulating inside Spanish, Portuguese and Polish.

A recent study in the journal Cancer Discovery found that inhalation of harmful microbes may contribute to advanced lung cancer in adults. Long-term use of face masks can help breed these dangerous pathogens, ”the article states.

It is based on one study published in the magazine Discovery of cancer, which makes no mention of masks, and also refers to local news report that recommends wearing masks during the pandemic, but warns readers to wash them regularly if they are reusable.

Study co-author Dr. Leopoldo Segal told AFP in an email that “our recent study does not involve wearing a mask, and there is no scientific reason or evidence to support the false idea that wearing a mask reduces the amount of oral bacteria reaching the lungs. , increases. “

Other experts agreed that there is no data to support the claims circulating online

Dr. Nicole Ezer, assistant professor in the Faculty of Medicine and Health Sciences at McGill University, said in an email that “there is currently no scientific evidence to conclude that masks increase the risk of lung cancer.”

And Dr. Gerard Cox said there is “no plausible link (mechanism for causing cancer) between wearing a PPE mask and developing lung cancer.” Cox, who also spoke by email, is a professor in the Faculty of Health Sciences at McMaster University.

The article shared on Facebook also refers to a local news report that recommends wearing masks during the pandemic, but warns readers to wash them regularly to protect them from fungi and bacteria if they are reusable.

Ezer, who also leads a lung cancer screening program at McGill University Health Center, stressed the importance of washing such masks. “The air you breathe already contains bacteria that live in your mouth, so wearing a mask doesn’t change that. If you haven’t washed your mask I might be concerned about new bacteria entering the mouth, but in general it is recommended that you wear disposable masks or wash reusable masks! “

Some of the messages on Facebook and Instagram use alleged quotes about oxygen starvation of the cells throughout Otto Warburg, who won the Nobel Prize in Physiology or Medicine in 1931 and died in 1970.

Screenshot of an Instagram post taken on Feb. 12, 2021

But science has evolved since Warburg’s time.

McGill’s Ezer explained, “What Warburg considered to be causal (lack of oxygen and acid causes cancer) is now considered to be the result of mutations in genes (oncogenes and tumor suppressor genes).”

“Warburg has made important scientific contributions to cellular metabolism, but his research really failed to establish a causal relationship, which is assumed in these Facebook posts,” she said.

The American Lung Association said in one blog post that “masks are designed to be breathable and there is no evidence that low oxygen levels occur.”

A group of global health professionals also published a rebuttal to the claim that masks cause cancer, to write: “Wearing a face mask does not increase your risk of cancer.”

“There is currently no evidence that the use of face masks is associated with cancer, and science shows that the risks associated with wearing masks are generally low, while the benefits are great … Health workers bear. often masks for long hours in the hospital and thus for a long time, ”said the experts.

AFP has invalidated many false or misleading claims about masks, including claims about bacteria, pneumonia and masks here and here.

EDIT: This article was updated on February 16, 2021 to add Dr Nicole Ezer's affiliation with the McGill University Health Center.

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