For many weeks now, countless studies have been carried out on the coronavirus. Among them, an analysis of 1,099 patients in China classified according to age, sex, medical history... but also according to patients' habits such as whether or not they smoke.Data that seems significantSeveral groups and associations are warning about the impact of smoking on people who are infected with Covid-19. This is the case with the French Alliance Against Tobacco, an association created in 1991 to 'accompany the proper application of the Évin law and measures to prevent against smoking.'In a briefing, the association stated that 'smoking increases the risk of developing a severe or very severe form of the disease.' The Alliance Against Tobacco relied on a study published on the 28th of February in The New England Journal of Medicine scientific journal, entitled 'Clinical Features of Coronavirus in China.'This study analysed the characteristics of 1,099 patients. On this panel, 927 never smoked, 21 were former smokers, and 137 were frequent smokers.Among the 927 who didn't smoke, 793 never had a severe form of Covid-19, and 134 did. Of the 158 smokers or former smokers, 120 did not develop a severe form of Covid-19, and 38 did. This represents 14.46% for non-smokers and 24.05% for smokers or former smokers.Figures to be taken with a grain of saltThe Alliance Against Tobacco said that 'data show a link between smoking status and the risk of developing a severe form' of Covid-19.Sandrine Belouzard, a researcher at the French scientific research centre CNRS, recently spoke to the LCI channel about the topic. 'People who smoke or were smokers have a greater risk of developing a severe form of Covid-19. Being a smoker can cause chronic bronchitis or respiratory diseases, which are then co-morbidity factors for this virus.'But one has to be careful with these numbers. A smoker's lung health is often worse than that of a non-smoker. Which can be an aggravating factor if a virus, like COVID-19, is contracted. But this study is based on just over 1000 cases, which is not that many. These cases are all Chinese, which implies that they all share very particular living conditions that are specific to this panel. It would take an international study of a larger scale to have a real idea on the topic.More chance of being infected if you smoke?In this study conducted by Chinese researchers, 927 infected people had never smoked and 158 were smokers or former smokers. An astonishing difference that does not really correspond to the percentage of smokers in China. It is therefore difficult to draw a conclusion about the impact of smoking on being infected with the coronavirus.After analysing the results of this study, Sandrine Belouzard explained to LCI that 'therefore, there is no proven link between smoking and being infected.'You would, therefore, have no more chances of being infected if you are a smoker, but on the other hand, if you are a smoker, this could make the coronavirus more dangerous. All this is still a hypothesis, to be taken with a grain of salt.