According to a meta-analysis of studies published on the question, smoking would increase the risk of complications in patients with Covid-19.
The controversy around tobacco and the Covid continues. While some said at the start of the epidemic that smokers seemed more protected from the virus than others, several studies have shown the opposite. Today, a meta-analysis (scientific method combining the results of a series of independent studies on a specific subject) published on May 12 in the newspaper Nicotine & Tobacco Research confirms that smoking would increase the risk of progression of Covid-19.
For researchers at the University of California, San Francisco (USCF, United States), conducting studies on the general population underestimates the risks of smoking in Covid-19. “The fact that the prevalence of smoking is lower in Covid patients than the general population has been cited as evidence of a protective effect of smoking”, explains Roengrudee Patanavanich, a researcher at UCSF in the Department of Medicine at Ramathibodi Hospital at Mahidol University (Thailand). In China, two studies published in February in The Lancet and the New England Journal of Medicine showed in particular that smokers were less infected with the coronavirus. “But this low prevalence may in fact be due to an undervaluation of smoking, especially considering the difficult conditions of caring for people in often overwhelmed health systems.”, explains Roengrudee Patanavanich.
Also, based on the observation that it was necessary to study directly infected patients, the researchers carried out a meta-analysis of 19 scientific articles published in PubMed. The latter, from China, Korea and the United States, included data on the smoking habits of patients with Covid-19 and the severity of their disease.
“A significantly higher risk of the progression of Covid-19”
The researchers were thus able to observe that out of 11,590 patients with Covid-19, 2,133 (18%) had suffered from disease progression. Among the patients followed, 731 or 6.3% of them had a history of smoking. Of these, 218 (29.8%) experienced disease progression compared to 17.6% of non-smoking patients. Thus the risk of progression of the disease in smokers or former smokers is almost double compared to patients who have never smoked, note the scientists.
In addition, when Covid-19 worsened, smokers developed more complications that could lead to death, they noted. “Smoking is associated with a significantly higher risk of Covid-19 progression,” comments Stanton A. Glantz, professor of medicine and director of the UCSF Center for Tobacco Control Research and Education.
This could be explained because tobacco would increase the risk of serious lung infections because of the damage done to the upper respiratory tract. It would also lead to a decrease in pulmonary immune function. Thus, smokers are more likely to suffer from pulmonary fragility and to develop chronic obstructive pulmonary disease, a chronic bronchial disease.
In 2012, when MERS-COV, Middle East respiratory syndrome, was discovered, several studies showed that smokers were more likely to be infected and die from this highly pathogenic coronavirus. In conclusion, to limit the spread of the new virus, the researchers of this meta-analysis recommend doing prevention around these associated risks.
Watch out for cigarette smoke
In France, health authorities have been campaigning since the start of the crisis to raise awareness among smokers about Covid. “As soon as there is a failure of the lung capacities, Covid-19 risks reinforcing these damages in a sometimes dramatic way.”, recalled in particular Franck Chauvin, president of the High Council for Public Health, at the Figaro 1er April.
According to the national committee against smoking, vapers and smokers are also more likely to contract the coronavirus because they put their fingers in their mouths, which increases the chances of getting the virus there. What’s more, passing a cigarette, whether electronic or not, or a joint further increases this risk. Finally, smokers are more likely to contaminate those around them.
Indeed, tobacco smoke contains particles to which the virus can cling. Outside, the clouds generated by cigarette or vape smoke can stretch for 10 meters, say the experts. “Smokers, vapers, for you and those around you, stop as soon as possibletherefore intimates Professor Yves Martinet, President of the National Committee against Smoking. Otherwise, do not smoke or vape at home. If you go out, go out alone and at a minimum distance of 10 meters from any person and any dwelling.” To quit smoking, you can contact the Tobacco Info Service number on 39 89 or on the dedicated application.
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