Nicotine is thought to have preventive properties against Covid-19. This is the hypothesis put forward by several scientists in a study published by the Academy of Sciences on Tuesday, April 21. But are the smokers really safe?
The study published, by the Academy of Sciences, is surprising. Researchers are wondering about the role of nicotinic acetylcholine receptor and the effectiveness of nicotine as a preventive and therapeutic measure against coronavirus.
Why ask yourself about the effects of nicotine?
First analyses show that smokers are less affected by Covid-19. Only 8.5% of patients admitted to hospitals for coronavirus at the beginning of April were smokers. This paradox is all the more surprising as tobacco consumption considerably increases the risk of contracting respiratory diseases such as chronic obstructive pulmonary disease (COPD).
However, a study conducted by the Pitié-Salpêtrière hospital in collaboration with the neurobiologist Jean-Pierre Changeux came to the same conclusion. “The study strongly suggests that daily smokers are much less likely to develop a symptomatic or severe infection with SARS-Cov-2 than the general population,” the study says. Of the 350 hospitalized and 130 outpatient patients (all Covid-19 positive), only 5% were smokers.
Therefore, nicotine (and not tobacco itself) is the focus of all attention. But “these lines of research remain hypothetical and their preventive effect on infectious diseases has not yet been proven,” stresses Bernard Basset, public health doctor and president of the French National Association for the Prevention of Alcohol and Drug Addiction.
What is nicotine?
“Nicotine is the molecule that causes tobacco addiction,” recalls Dr Basset. By attaching itself to its own receptors (cholinergic nicotine receptors), it stimulates the production of dopamine. It is therefore known for its effect on nerve cells in the central nervous system, ‘but it is not a molecule that is often used as a therapy’, although some studies have considered it to be beneficial for Parkinson’s disease.
What effects does nicotine have against the coronavirus?
According to researchers, nicotine could prevent the binding and penetration of SARS-CoV-2 into cells, thus limiting the spread of SARS-CoV-2. “It is known that SARS-CoV-2 uses the ACE2 receptor to enter cells, and there is evidence that nicotine modulates the expression of ACE2, which in turn can modulate the nicotine and acetylcholine receptor,” says the study.
But another hypothesis suggests that nicotine can also reduce the excessive immune response that is characteristic of the most severe cases of COVID 19. Researchers remain cautious and expect observations from future clinical trials.
Are smokers still protected against the coronavirus?
It should not be concluded that tobacco smoke has a protective effect because it contains thousands of toxic components, about 50 of which are carcinogenic. The message is certainly not: start smoking! Its health damage has been proven and we should not raise false hopes. Until proven otherwise, tobacco remains the main preventable cause of death in the US. Because even if they seem less affected, smokers affected by the coronavirus are likely to develop more serious infections than non-smokers.
As for electronic cigarettes, which also provide nicotine, it is still too early for researchers to make a statement. Apart from the coronavirus epidemic, its health consequences remain controversial. Although many studies have shown that electronic cigarettes have helped a large number of smokers quit, in a report published in July 2019, the WHO stated that “the long-term effects of electronic nicotine inhalers remain unknown” and warns in particular of the risk of respiratory irritation. In addition, cigarette smoke and vapers vapor remain potential vectors for COVID 19: they may contain virus particles that can be inhaled by those around.
What are the clinical studies on nicotine?
With the help of the French Ministry of Health, therapeutic trials and a clinical trial are being conducted to test the effectiveness of nicotine. Nicotine patches are administered in different doses to nurses (as a preventive measure), to hospitalized patients (to evaluate the reduction in the symptoms of coronavirus) and to patients in intensive care units (to see if their inflammatory condition improves).
There is no need to run to pharmacies for nicotine replacement patches. It makes no sense to use these nicotine devices if you’re not a smoker and you don’t want to quit, especially if the decision is motivated by an unproven hypothesis.