A total of ninety-five articles were found, including a large number of letters related to the paradoxical links between tobacco or nicotine and COVID-19. A total of 40 articles was included for this review (after exclusions of doublons and non-related abstracts). Ten were reviews (Engin et al., 2020; Gasmi et al., 2020; Olds and Kabbani, 2020; Vardavas and Nikitara, 2020) or meta-analysis or letters with pooled analysis (Alqahtani et al., 2020; Emami et al., 2020; Farsalinos et al., 2020b; Lippi and Henry, 2020; Zhao et al., 2020; Zheng et al., 2020). Smoking could be a key predisposing factor for COVID-19-related illness severity and mortality based on a recent study of 1590 patients from 575 hospitals across China (Guan et al., 2020a). The first publications reported a link between male sex and COVID-19, possibly underpinned by cigarette smoking (which prevalence is higher for Chinese males (around 50%, against around 3% for females) (Guan et al., 2020a; Wang et al., 2020). Tobacco use was associated with a more severe form of the disease (16.9% of tobacco use in severe cases vs 11.8%
