Frontline health workers and patients in France may be given nicotine patches after studies found that four times fewer smokers contracted Covid-19 than non-smokers.
It may sound counterintuitive that people who puff on Gauloises are less likely to catch a virus that can cause deadly attacks on the lungs. However, that was the statistical outcome of an in-depth study conducted by the Pasteur Institute, a leading French research centre into the disease.
The institute tested almost 700 teachers and pupils of a school in Crépy-en-Valois in one of the hardest-hit areas in France, as well as their families. The “highly accurate” tests found that only 7.2 per cent of smokers from among the adults tested were infected while four times as many non-smokers, some 28 per cent, were infected.
Arnaud Fontanet, an epidemiologist at the institute, warned that they were not encouraging people to take up smoking, remarking that those smokers who do catch the virus “risk suffering more complications” than others. Scientists suggested it could be the nicotine in cigarettes that was behind the surprising results regarding infection, although more research is needed.
A study from China prompted Public Health England and the Centers for Disease Control and Prevention in the United States to put smoking on the list of ‘risk factors’ for coronavirus earlier in the crisis.
Public Health England said: “Smoking tobacco is known to damage the lungs and airways causing a range of severe respiratory problems. The evidence clearly shows Covid-19 virus attacks the respiratory system, which explains why smokers are at greater risk. A small but highly impactful survey from China finds that smokers with Covid-19 are 14 times more likely to develop severe disease.”
However, the Pasteur Institute results appear to tally with another study by the Pitié-Salpêtrière Hospital in Paris, which questioned 480 patients who tested positive for the virus.
According to their findings, among the 350 patients hospitalised, whose median age was 65, only 4.4 per cent were regular smokers. Among those released home, with a median age of 44, 5.3 per cent smoked.
The French health authority Santé Publique France puts the number of smokers in the general population at 32 per cent of people between 18 to 75 years old.
“Compared to the French general population, the Covid-19 population exhibited a significantly weaker current daily smoker rate by 80.3 per cent for outpatients and by 75.4 per cent for inpatients,” the researchers wrote in their study.
“Thus, current smoking status appears to be a protective factor against the infection by SARS-CoV-2.”
The researchers said that a “nicotinic acetylcholine receptor (nAChR)” plays a key role in infection from the coronavirus and that nicotine may act to protect this receptor from attack. It may also lessen the overreaction of the body’s immune system that has been found in the most severe cases of Covid-19 infection.
Clinical trials of nicotine patches on health workers and patients are awaiting the approval of the country’s health authorities.
Health minister Olivier Véran called the study “interesting”, adding: “We will not be shutting any doors and certainly not that one.”
Smoking causes 75,000 deaths in France and researchers were at pains to point out that nobody should take up the habit as a preventative measure.
“One should not forget that nicotine is a drug of abuse responsible for smoking addiction,” they wrote.
“Smoking has severe pathological consequences and remains a serious danger for health. Yet under controlled settings, nicotinic agents could provide an efficient treatment for an acute infection such as Covid-19,” they concluded.