On February 9, Chinese academician Zhong Nanshan published a retrospective study on novel coronavirus cases in medRxiv, a medical preprint magazine. According to Zhong’s paper “Clinical characteristics of the 2019 novel coronavirus infection in China” of 1099 new coronavirus patients, 927 were never smokers (85.4%), 21 are ex-smokers (1.9%) and 137 are current smokers (12.6%). The proportion of smokers in the Chinese population is 28.1%. These data seem to indicate that smokers are far less likely to be infected with the novel coronavirus than non-smokers.(1)
On April 22, France Inter reported that a research team from the Pitie-Salpetriere Hospital in Paris, led by Jean Pierre Changeux, a member of the French Academy of Sciences, launched research asking “Can nicotine protect the human body from invasion by the novel coronavirus?” The reason is that field surveys of new patients with novel coronavirus show a puzzling fact: compared with non-smokers, smokers are less likely to be infected.
The Paris researchers surveyed 350 hospitalized patients and 130 patients with mild symptoms who did not need to be hospitalized. Based on total population data from 2018, the researchers wanted to check whether these patients smoked more than other people of the same gender and age. The conclusion is that smokers are very rare among these patients.”We found that only 5% of these patients are smokers. It’s a low proportion. In general, the proportion of smokers is 80% less than other coronavirus-infected patients of the same gender and age,” explained Zahir Amoura, a professor of internal medicine.
On the other hand, Jean Pierre Changeux speculated that nicotine may prevent the coronavirus from attaching to objects and human surfaces. Furthermore, it may prevent the coronavirus from invading cells. This may mean nicotine can inhibit the spread of virus and the novel coronavirus pneumonia.(2,3)
According to Israel’s Jerusalem Post on June 7, Israeli scientists found that smoking can provide some protection against the novel coronavirus. The results are similar to those of researchers in China, France and Italy.
Since there were conflicting reports about the impact of smoking on the risk of contracting novel coronavirus, an Israeli team led by Dr Ariel extracted data from more than 3 million adult members of Clalit, Israel’s largest health service center. Novel coronavirus pneumonia seems to be reduced by half in smokers, according to the result of their research.
Of the more than 3 million adults involved in the study, 114,545 were tested for the virus, of which only 4% were positive. The researchers matched people who tested positive to those who tested negative in a ratio of 1:4, taking into account as many variables as possible, such as age, gender and race. They found that among those who tested positive, smokers accounted for 9.8% and 19% of the total population.
Smoking seems to bring some benefits, with 11.7% of those who tested positive had a history of smoking, compared with 13.9% of the general population in the study. As a result, the study showed that people with a history of smoking had a 19% lower risk of contracting the virus.(4)
The study by Professor Zahir of the Pitie Salpetriere Hospital also showed that smokers are about half as likely to be infected as other people. Of the novel coronavirus pneumonia patients who visited the hospital from February 28th to April 9th, only 4.4% of inpatients and 5.3% of outpatients smoked daily, compared with 25.4% in the general population. The study also found that smokers were 80% less likely to have severe symptoms, leading researchers to suggest that the free-state nicotine in cigarettes binds to cell receptors to block the virus.
Similarly, a study of 28 papers by University College London showed that the number of smokers infected with coronavirus was “lower than expected”; A Chinese study also found that only 6.5% of 5,300 hospitalized patients with coronavirus were smokers; A study by the Centers for Disease Control and Prevention in the United States found that only 1.3% of the more than 7000 people who tested positive were smokers, the Daily Mail of Britain reported.”Our results provide compelling evidence for the current association between smoking and an individual’s risk of COVID-19 infection,” the researchers wrote in the paper.(6)
“The potential benefit of free-state nicotine is that it can partly explain the exacerbation or adverse consequences of smokers hospitalized for coronavirus. It is because these patients will inevitably stop taking nicotine during hospitalization,” Dr. Constantinos Fasalinos from the University of Siatica, Greece, wrote in his paper for internal medicine and emergency medicine.(7)
On February 2, experts in Shenzhen, China started relevant research on the IUOC, a heat-not-burn tobacco device, which attracted their attention. The nicotine produced by one cigarette heated by IUOC is the same as that produced by a lighted one, which is free-state nicotine. But the amount of nicotine released by a heat-not-burn cigarette is twice that of a lighted one, and it is almost pure nicotine aerosol. On July 1st, researchers found that more than 600 cigarette stores in Beijing were selling the IUOC device.
Shenzhen Yukan Technology Co., Ltd.
Rm 1110, West Tower, Nanshan Software Park,
No.10128, Shennan Road, Nantou Street, Nanshan District, Shenzhen, China
(3) https://www.qeios.com/read/FXGQSB (A nicotinic hypothesis for Covid-19 with preventive and therapeutic implications)