A health clinic in San Francisco during the Spanish flu pandemic.
People at a health clinic in San Francisco during the Spanish flu pandemic in 1918. Image by EPA

Spanish flu pandemic claim masks the truth about deaths

Kate Atkinson May 26, 2022

The vast majority of deaths during the Spanish flu pandemic in 1918-19 were due to bacterial infections caused by people wearing masks.


False. Many people succumbed to bacterial pneumonia due to lung and immune system damage following influenza virus infection. There is no evidence mask use was the cause.

An Australian Facebook user claims the majority of deaths during the Spanish flu pandemic a century ago were due to people wearing masks, not the influenza virus.

The claim was made in a post (screenshot here) on May 10 alongside screenshots of two other Facebook posts including an Israel National News article with the headline, “New study: Face mask usage correlates with higher death rates”.

“Most people don’t realise but the vast majority of the deaths during the Spanish flu were NOT actually attributed to the flu virus but rather widespread bacterial infections as a result of wearing masks,” the text in the post reads.

The claim is false. While many deaths during the 1918-1919 pandemic were associated with secondary bacterial infections, evidence shows they were caused by the influenza virus – not mask use.

The Spanish flu was the most severe pandemic in recent history. The US Centers for Disease Control and Protection estimates about one-third of the world’s population became infected and at least 50 million people died.

A 2008 study by David Morens, Jeffery Taubenberger and Anthony Fauci examined tissue sections obtained during autopsies and found the majority of deaths in the 1918-19 pandemic likely resulted “directly from secondary bacterial pneumonia caused by common upper respiratory-tract bacteria”.

They found pneumonia was caused when bacteria that normally “inhabit the nose and throat invaded the lungs along a pathway created when the virus destroyed the cells that line the bronchial tubes and lungs”.

Other scientific papers here, here and here confirm bacterial pneumonia often develops after a person becomes sick with influenza.

Justin Denholm, a professorial research fellow at the University of Melbourne’s Department of Infectious Diseases, says during the 1918-1919 pandemic “there were well-documented ‘waves’ of illness, and very likely a good deal of this happened because of bacterial infections (staphylococcus and streptococcus) that follow 1-2 weeks after influenza infection and can cause very severe bacterial pneumonia”.

“We still see this today, and after influenza now we will often see these bacterial infections in the same pattern,” he told AAP FactCheck in an email.

Prof Denholm said the problem with the post’s claim was masks “are in no way implicated” in the secondary bacterial infection process.

“The bacterial infections come because of damage done to the lungs and immune system from the influenza virus itself. There’s no suggestion that masks cause or make this worse, and from a public health point of view, mask wearing is of course a critically important part of limiting the spread of infection.”

Keith Klugman, professor of global health in the Rollins School of Public Health at Emory University, told AAP FactCheck in an email the claim face masks caused the bacterial pneumonia deaths is “total nonsense”.

Prof Klugman agrees the bacterial-associated deaths which occurred during the pandemic were caused by the influenza virus.

AAP FactCheck also consulted Dr David Hamer, a professor of global health and medicine at Boston University Schools of Public Health and Medicine, and Dr David Muscatello, an associate professor in infectious diseases epidemiology at the University of NSW.

Both say there’s no evidence wearing masks causes widespread bacterial infection.

“There’s certainly no evidence of it with COVID, as far as I know,” Dr Muscatello said in an email.

Dr Hamer says it’s unlikely wearing masks contributed to bacterial infections during the 1918-1919 pandemic and “recent mask use studies in the context of COVID-19 that have shown the safety of this approach and there are no data, that I am aware of, that suggest mask use in the current pandemic has resulted in increased rates of bacterial infections”.

Similar claims have been debunked here and here, while AAP FactCheck has previously debunked the claim face masks can cause illnesses.

The Verdict

The claim the majority of the deaths during the Spanish flu pandemic were a result of wearing face masks is false. Most deaths during the 1918-1919 outbreak were caused by bacterial pneumonia following influenza infection. Experts told AAP FactCheck there is no evidence mask use contributes to people developing bacterial infections.

False – The claim is inaccurate.

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