News

South Africa is the only country to still have a tobacco ban (and was only ever one of three to impose it) while many major European countries such as France, Spain and Italy even exempted tobacco kiosks from their various lockdowns. This was on the basis that they provide an essential service.

As early as April in the Covid-19 outbreak, researchers noticed that the virus disproportionately affected non-smokers compared to smokers. A group of French academics shortly thereafter published a study of 343 Covid-19 patients, of whom only 4.4% were daily smokers. According to the authors, the study “strongly suggests that daily smokers have a very much lower probability of developing symptomatic or severe SARS-CoV-2 infection as compared to the general population”. This prompted Professor Jean-Pierre Changeux to go public with his more detailed research project.

The potentially therapeutic effects of nicotine had previously been noted in 2014 by Harvard Medical School. In its online publication Harvard Health Publishing in an article entitled Nicotine: It may have a good side it notes that while it gets people hooked on cigarettes, researchers hope that nicotine and related compounds will have therapeutic uses.

“Nicotine is rightly reviled because of its associations with smoking and addiction. But the rogue substance has a wide range of effects on the brain, which may include some healing properties. Researchers are testing nicotine and related compounds as treatments for Alzheimer’s disease, Parkinson’s disease, attention deficit/hyperactivity disorder (ADHD), and other conditions.”

In an article published in Qeios, titled A nicotinic hypothesis for Covid-19 with preventive and therapeutic implications, French authors Changeux, Zahir Amoura, Felix Rey and Makoto Miyara state: “SARS-CoV-2 epidemics raise a considerable issue of public health at the planetary scale. There is a pressing urgency to find treatments based upon currently available scientific knowledge. Therefore, we tentatively propose a hypothesis which hopefully might ultimately help in saving lives. Based on the current scientific literature and on new epidemiological data which reveal that current smoking status appears to be a protective factor against the infection by SARS-CoV-2, we hypothesise that the nicotinic acetylcholine receptor (nAChR) plays a key role in the pathophysiology of Covid-19 infection and might represent a target for the prevention and control of Covid-19 infection.

“A potential protective effect of smoking and of nicotine on SARS-CoV-2 infection has been noted. Until recently, no firm conclusions could be drawn from studies evaluating the rates of current smokers in Covid-19. All these studies, although reporting low rates of current smokers, ranging from 1.4% to 12.5%, did not take into account the main potential confounders of smoking, including age and sex. In the study that two of us are reporting, the rates of current smoking remain below 5% even when main confounders for tobacco consumption, i.e. age and sex, in- or outpatient status, were considered. 

“Compared to the French general population, the Covid-19 population exhibited a significantly weaker current daily smoker rate by 80.3% for outpatients and by 75.4% for inpatients. Thus, current smoking status appears to be a protective factor against the infection by SARS-CoV-2.”

These findings are widely ridiculed by health authorities, potentially because such authorities do not want them to be true, and because they don’t approve of smoking and smokers. Obviously smoking in its own right is one of the biggest health risks, but this does not mean that nicotine might not be helpful in this particular case.

Research similarly suggests that ex-smokers with inflammatory bowel disease (IBD) often only develop symptoms when they give up smoking: that is, that smoking/ nicotine is in some way protective. Both IBD and Covid-19 involve aggressive immune responses so there may be some connection in the way that nicotine helps. Such findings should ideally prompt the logical response “that’s interesting, let’s do some more research” not “smoking is bad and therefore this cannot be true”.

So emphatic was the research in France that the government moved to prevent the stockpiling of nicotine patches (by people buying them as a preventative measure against Covid-19) after the country’s health minister expressed interest in research suggesting that the addictive stimulant could help lessen Covid-19 infection.

It follows the publication of a study on 483 patients at Pitié-Salpêtrière Hospital in Paris, which reported that the infection rate for smokers among Covid-19 outpatients and inpatients was significantly lower than for non-smokers. Only 5.3% of the Covid-19 patients were smokers, while 25.4% of the general population smoke regularly. 

The research said nicotine was the “likely” reason, while stressing that using tobacco remained a danger to public health, killing almost 80 000 people per year in France.

French Health Minister Olivier Véran gave a positive assessment on the findings, saying on France Inter radio that it was “an interesting possibility” and that he had given his approval for further research. “We’ll know more soon,” he added, while urging people not to self-medicate with nicotine patches. He noted the harmful effects of smoking must absolutely not be forgotten. Jérôme Salomon, French director-general of health, says: “Smoking is the number one killer in France?.?.?.?do not confuse research hypotheses with proven effects.”

Not conclusive

Research into the impact of smoking and nicotine in Covid 19 cases remains preliminary and patchy. Changeux, the neuroscientist who reviewed the Pitié-Salpêtrière study, suggested nicotine may bind to the same receptors as the Coronavirus, making it harder for the disease to take hold. “Under controlled settings, nicotinic agents could provide an efficient treatment for an acute infection such as Covid-19,” he says.

However, smokers that do contract Covid-19 are more likely to progress to the severe stage. Research in the New England Journal of Medicine from Covid-19 patients in China, shows that these impacts were seen among smokers with Covid-19. “Among the research cohort, smokers were about 1.5 times more likely to see their disease progress to the severe stage compared to non-smokers,” says 

Deborah Arnott, Chief Executive of the anti-smoking charity Ash. She also says the planned French trial “should not put smokers off trying to quit”.

However, Linda Bauld, Professor of Public Health at the University of Edinburgh in the UK — who was not involved in the French study — says it was not entirely unexpected that nicotine could have an impact, as other studies had indicated there was “something weird going on with smokers and coronavirus”.

“All over the world, we are trying to repurpose existing medicine to fight the pandemic, so it makes sense the French are investigating this,” said Bauld.

A second French study of an infection cluster in the Oise department north of Paris made a similar finding about smokers in the course of its analysis of the 661 people it tested. It found smokers had a lower infection attack rate of 7.2% compared with 28% for non-smokers.

Resource