Epidemiological studies show that smokers are underrepresented among the patients hospitalized for COVID-19. In fact, only 1 to 6% of hospitalized patients are smokers, but they represent 14 to 25% of the general population.
Mathieu Morissette from the Laval University Medical department says that smokers are not just exposed to nicotine, but many other chemical compounds. If we suppose that nicotine is beneficial, it does not protect from the disease, but rather prevents severe symptoms. Other hypotheses are that nicotine could have an effect on the cytokine storm in COVID-19.
Jean-Benoit Legault, La nicotine contre le coronavirus? Pas si vite. La Presse. April 24, 2020.