If you noticed headlines recently suggesting smoking could protect against COVID-19, you might have been surprised.
After all, we know smoking is bad for our health. It’s a leading risk factor for heart disease, lung disease and many cancers. Smoking also reduces our immunity, and makes us more susceptible to respiratory infections including pneumonia.
And smokers touch their mouth and face more, a risk for COVID-19 infection.
As a cardiologist with a career devoted to tobacco harm reduction, I obviously closely monitor health developments in the country that consumes approximately one third of the planet’s cigarettes.
So, when COVID-19 was already on its relentless march around the globe earlier this year, I was struck by one apparently paradoxical statistic that kept standing out in the blizzard of new data emerging from China, ground zero of the disease.
Initial observational findings suggested a history of smoking increased the risk of poor outcomes in COVID-19 patients, as the World Health Organisation and other bodies have identified.
But a recent paper which examined smoking rates among COVID-19 patients in a French hospital hypothesised smoking might make people less susceptible to COVID-19 infection.
The Chinese are amongst the biggest smokers in the world, with more than half of all adult men indulging in the habit.
In a country where 26.6% of all adults smoke (approximately 50% among men), very few of those hospitalized seemed to be smokers.
COVID-19 is an illness that affects the lungs and airways; smoking is not, and should not be, associated with anything positive when it comes to the human respiratory system.
Scientists are obliged to examine and interrogate the facts, no matter how counter-intuitive they initially appear to be.
However, we are exploring and have identified potential mechanisms through which pharmaceutical nicotine could act in COVID-19, and the findings so far look promising. If verified in laboratory and clinical studies, the implications will go far beyond smoking or use of other nicotine products.
There is no doubt that smoking cannot be used as a protective measure, and none should take up smoking in order to prevent themselves from contracting the virus.
That would be very unwise for a plethora of health reasons already settled by overwhelming science.
However if, as I suspect, nicotine is a protective mechanism against COVID-19, public health organisations and governments have a duty to seriously consider the evidence.
In South Africa, the only country to have prohibited the sale of all traditional as well as new delivery methods of nicotine (cigarettes, tobacco heated products and e-cigarettes) to, ostensibly, combat the spread of the virus, lawmakers may have to ponder whether their approach is likely to have the intended outcome or if it can actually have disastrous consequences.
So back to the peer-reviewed findings, which some find so upsetting.
I performed a systematic literature review of 13 COVID-19 studies, focusing on hospitalisation data, classifying patients into less and more severe disease status.
My analysis found that among 5 960 patients in hospital with the diagnosis, 450 were current smokers. The prevalence of smokers was 7.5%.
Remember, that’s in a country where 26.6% of people smoke.
These seemingly remarkable results have been echoed in other research in France, US and Germany.
At the University Hospitals Pitié Salpêtrière, in Paris, a team of researchers led by neuroscientist Jean-Pierre Changeux found that 4.4% of 343 hospitalised patients were smokers.
Out of 139 outpatients involved in the study, 5.3% were recorded as smokers. Again, these are very low numbers, in a nation where one-fourth of the population smokes.
The Pitié Salpêtrière report authors wrote: “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 effect is significant. It divides the risk by five for ambulatory patients and by four for those admitted to hospital. This is an unprecedented finding that cannot be ignored.”
In the US, the Center for Disease Control reports that in a study of 7 162 patients only 1.3% were current smokers, while the national population smoking prevalence is 13.8%.
Additionally, a small case series from Germany presented 50 Covid-19 patients of whom only three (6.0%) were current smokers.
All these studies have reflected the same thing: a remarkably low number of smokers appear to be developing severe COVID-19 to the degree that they need hospital treatment.
Why this might be so, is obviously a matter of great global importance, interest and debate. COVID-19 has been with us for a matter of months and significant further studies are required.
My own hypothesis is, essentially, that nicotine has certain anti-inflammatory effects. The most severe COVID-19 symptoms seem to come from an overreaction of the body’s immune system known as a “cytokine storm”.
During that storm, the immune system over-reacts in response to an infection, say in the lungs, and they can become overly inflamed, leading to substantial tissue damage.
Nicotine might be able to, at least, dampen that intensity.
In South Africa, President Ramaphosa’s government has opted for prohibition of nicotine and smoking, although reports would seem to suggest that there is a thriving black market.
Their reasoning has been based on smoking’s undeniable links to heart attacks, cancer and lung disease.
The government also appears to have pointed to some studies which show that when smokers are hospitalised with COVID-19 they may be at a higher risk of experiencing negative and severe progression of symptoms.
However, they never considered that smokers experience abrupt nicotine cessation when hospitalised.
None is giving them nicotine substitutes when hospitalised, and the effects of nicotine will be weaned off within hours from hospitalisation.
Nicotine cessation may in fact be damaging for these patients.
But there is no clinical evidence that current smoking is a predisposing factor for hospitalization for COVID-19.
On the contrary, the data I and other experts have studied, suggests that current smokers are significantly less likely to be hospitalised.
I, and others, believe this is because of nicotine and cannot be attributed to the effects of other toxins emitted in tobacco cigarette smoke.
And that is why significant further research is already under way.
– Konstantinos Farsalinos, MD, MPH is a cardiologist and research fellow at the Onassis Cardiac Surgery Center in Athens-Greece, at the Department of Pharmacy, University of Patras-Greece and at the National School of Public Health-Greece.
He is specialized in echocardiography and in smoking and tobacco harm reduction research.
He was the lead researcher in Inter-vendor Study, a joint research project of the European and American Societies of Echocardiography.
He has been conducting laboratory, clinical and epidemiological research on smoking, tobacco harm reduction and e-cigarettes as principal investigator since 2011.
As of 2019, he has published more than 70 studies and articles in international peer-reviewed scientific journals about smoking, tobacco harm reduction, and e-cigarettes. He was the handling editor and author in a book titled “Analytical assessment of e-cigarettes”, published by Elsevier in 2017.