French study: Smoking may offer some protection against COVID-19

A COVID-19 study in the Paris hospital network found that the percentage of patients who are also regular smokers was dramatically less than the percentage of smokers in the general population. The findings suggest smoking may offer some protection against the disease, researchers say. less A COVID-19 study in the Paris hospital network found that the percentage of patients who are also regular smokers was dramatically less than the percentage of smokers in the general population. The findings ... more Photo: Lillian Suwanrumpha, AFP/Getty Images Photo: Lillian Suwanrumpha, AFP/Getty Images Image 1 of / 3 Caption Close French study: Smoking may offer some protection against COVID-19 1 / 3 Back to Gallery

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A Paris hospital network study suggests that regular smokers may be safer from COVID-19 infection than the general public, according to reports by Radio France Internationale and the Guardian.

Researchers from multiple institutions found that of the roughly 11,000 patients hospitalized in the city’s public hospitals for the coronavirus at the start of April, only 8.5 percent were smokers, compared to 25.4 percent of the general public.

But the study’s authors warned that the findings should not be viewed as a carte blanche to start smoking cigarettes. The dangers of the habit are well-documented: It causes heart disease and lung cancer, and kills half of those who take it up.

Moreover, the smokers who did catch COVID-19 often developed more severe symptoms because of the cumulative damage caused by tobacco smoke to the lungs.

French researchers intend to test nicotine patches on coronavirus patients and frontline health care workers, according to the Guardian. Clinical trials are planned but must be approved by French health officials first.

The study took a closer look at 482 patients at the Pitié-Salpêtrière hospital who tested positive for the coronavirus. Of those, 343 were hospitalized with the remainder, whose symptoms were less serious, being sent home.

The smoking rate of the hospitalized patients, whose median age was 65, was 4.4%. Of those treated at home, whose median age was 44, 5.3% smoked.

Those figures might not be that surprising in the United States, where only 14 percent of adults smoke. In France, however, about 40% of those aged 44-53 and between 8.8% and 11.3% of those aged 65-75 are smokers, according to French health authority Santé Publique France.

“Our cross-sectional study strongly suggests that those who smoke every day are much less likely to develop a symptomatic or severe infection with Sars-CoV-2 compared with the general population,” the Pitié-Salpêtrière report authors wrote.

“The effect is significant. It divides the risk by five for ambulatory patients and by four for those admitted to hospital. We rarely see this in medicine.”

The Guardian reported that French neurobiologist Jean-Pierre Changeux, who reviewed the study, suggested the nicotine might stop the virus from reaching cells in the body, preventing its spread. Nicotine may also inhibit the body’s immune system from overreacting in the “cytokine storm” effect found in the most serious cases of COVID-19 infection.

But the chief of France’s national health agency, Jerome Salomon, cautioned that the nicotine link is only an unproven hypothesis at this stage.

The findings confirmed those of a Chinese COVID-19 study published last month in the New England Journal of Medicine. That report found that 12.6% of 1,099 of COVID-19 patients were smokers, while the smoking rate in China is around 28%.

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Mike Moffitt is an SFGATE Digital Reporter. Email: moffitt@sfgate.com. Twitter: @Mike_at_SFGate





