What do we know about the likely protective effect of nicotine against Covid-19?

Among the hundreds of harmful components present in cigarette smoke, one of these could have protective properties against Covid-19: nicotine. Observed for several months, the positive effect of this substance was analyzed by many researchers, and a three-phase study was started in Paris. Here’s what we know.

Less sick among smokers

The discovery does not date back to yesterday. Since April 10, when France did not finish the first month of imprisonment, the president of the scientific council, Jean-François Delfraissy, has noticed “something very special with tobacco”. “We found that the vast majority of cases are non-smokers, as if (…) tobacco was protected from this virus, through nicotine,” he said.

Since then, many researchers have looked into the issue, in France and abroad, confirming this trend: “We see overall that we have a risk of having Covid which is four to five times lower for a smoker than for the same-sex population. and of the same age “, reports Professor Zahir Amoura, head of the department of internal medicine 2, autoimmune and systemic diseases at the Pitié-Salpêtrière hospital in Paris.

At this point, an important reminder is needed: tobacco is inherently harmful to health and these findings do not constitute an encouragement to smoke to protect yourself from Covid-19.

How to explain these results?

To understand this phenomenon, Zahir Amoura and neurobiologist Jean-Pierre Changeux examined the role of the “nicotinic acetylcholine receptor”. “This nicotinic receptor has strong links with the virus’ portal of entry into cells, which is the ACE2 receptor,” explains Zahir Amoura. “We imagine that if we block the nicotinic receptor, we modulate the ACE2 receptor in one way or another, which could have an impact on the penetration of the virus into cells,” continues the researcher.

If the links between these two receptors were confirmed, this would explain why nicotine is able to slow down the virus’ entry into the body. Clearly, it could form some kind of protective barrier that would prevent the virus from entering cells, thus avoiding developing the disease.

Three studies

It is this theory that the AP-HP researchers will try to prove through three studies, two of which are already underway. They consist in distributing as many nicotine patches to non-smokers as there are placebos.

The first two studies concern patients already affected by Covid-19, hospitalized in a care unit (Nicovid study) and in an intensive care unit (Nicovid Rea). “The goal is to know if nicotine protects patients from developing towards a poor prognosis,” emphasizes Zahir Amoura.

The third study (Nicovid Prev) will focus on 1,633 non-smokers (doctors and hospital staff, private doctors, nursing home staff). They too will wear nicotine patches, or placebos, for about six months: “We are taking a population exposed to the risk of contracting Covid,” says the professor. The idea is to see if wearing these patches allows this. to see fewer infections. ”If the results are conclusive, the prospect of developing a nicotine-based treatment might be considered.