The smoker's paradox during the COVID-19 pandemic? The influence of smoking and vaping on the incidence and course of SARS-CoV-2 virus infection as well as possibility of using nicotine in the treatment of COVID-19 - Review of the literature.

AIM OF THE STUDY: The study aims to present the current state of knowledge on the impact of traditional cigarettes and the nicotine contained in them on the incidence and course of SARS-CoV-2 infection. Moreover, we decided to exhibit the possibility of using this substance to treat COVID-19 infections.

MATERIAL AND METHODS: The latest available scientific publications were reviewed until November 14, 2020, from the PubMed platform.

RESULTS: Nicotine is a cholinergic agonist and pro-inflammatory cytokines inhibitor. Some authors present that smoking and nicotine reduce the amount of the ACE2 receptors which are used by the novel coronavirus to enter cells, while others claim that ACE2 receptors are upregulated in smokers. Moreover, the interaction of SARS-CoV-2 with nAChR is suspected of dysregulation of the nicotinic cholinergic system, which is associated with the pathophysiology of COVID-19. Due to the harmfulness of cigarettes, a high frequency of smokers is suspected among people suffering from COVID-19. However, some studies report that the number of current smokers hospitalized for SARS-CoV-2 infection is lower than expected, considering the prevalence of smoking in individual countries. Nicotine could restore the impaired function of the nicotine cholinergic system and possibly mitigate the cytokine storm.

CONCLUSIONS: There is no clear attitude regarding the impact of smoking on the new coronavirus infection now. Researchers do not recommend smoking as a tool to combat the pandemic and show the importance of fighting addiction to reduce the adverse health effects of smoking. Both the relationship between cigarettes and the morbidity and severity of COVID-19, as well as the possibility of using nicotine in the treatment of the disease, require further analysis.