Tobacco product use and the risks of SARS-CoV-2 infection and COVID-19: current understanding and recommendations for future research.

Heterogeneity in the clinical presentation of SARS-CoV-2 infection and COVID-19 progression underscores the urgent need to identify individual-level susceptibility factors that affect infection vulnerability and disease severity. Tobacco product use is a potential susceptibility factor. In this Personal View, we provide an overview of the findings of peer-reviewed, published studies relating tobacco product use to SARS-CoV-2 infection and COVID-19 outcomes, with most studies focusing on cigarette smoking in adults. Findings pertaining to the effects of tobacco product use on the incidence of SARS-CoV-2 infection are inconsistent. However, evidence supports a role for cigarette smoking in increasing the risk of poor COVID-19 outcomes, including hospital admission, progression in disease severity, and COVID-19-related mortality. We discuss the potential effects of tobacco use behaviour on SARS-CoV-2 transmission and infection, and highlight the pathophysiological changes associated with cigarette smoking that could promote SARS-CoV-2 infection and increased disease severity. We consider the biological mechanisms by which nicotine and other tobacco product constituents might affect immune and inflammatory responses to SARS-CoV-2 infection. Finally, we identify current knowledge gaps and suggest priorities for research to address acute and post-acute health outcomes of COVID-19 during and after the pandemic.
Competing Interests: Declaration of interests NLB reports honoraria from McGraw Hill (for a chapter on “Antihypertensive agents” in Basic and Clinical Pharmacology) and Wolters Kluwer (for a chapter on the “Cardiovascular effects of nicotine” in UpToDate), payment for expert testimony against tobacco companies, and consulting fees from Pfizer and Achieve Life Sciences. NLB and MLG were speakers at the 2017 Global Nicotine Forum; they received no reimbursement from the tobacco industry for this role and the conference received no sponsorship from tobacco companies, e-cigarette companies, or the pharmaceutical industry. MLG reports ad-hoc consultancy fees from WHO, the US Food and Drug Administration (FDA), the Campaign for Tobacco-Free Kids, the University of South Carolina, and the University of North Carolina; honoraria for lectures from the University of Rochester, Memorial Sloan Kettering Cancer Center, and the University of South Carolina; reimbursement for travel from WHO and the International Association for the Study of Lung Cancer; and consultancy fees from Johnson & Johnson. MLG has a leadership role as a member of the Tobacco Products and Cancer Subcommittee of the American Association for Cancer Research and is a member of the Tobacco Control and Cessation Committee of the International Association for the Study of Lung Cancer. SK-S is the President of the Society for Research on Nicotine and Tobacco. PML is a member of the California Tobacco Education and Research Oversight Committee. BH-F reports payment for expert testimony in e-cigarette litigations and volunteer membership on the board for Parents Against Vaping E-cigarettes. RJO'C reports consultancy fees from the National Institutes of Health, WHO, Georgetown University, and the FDA; he also reports payment from the British Medical Journal for his work as Senior Editor, and support for travel and meeting attendance from WHO, the FDA, and Georgetown University. MAP, RMR, and AB declare no competing interests.
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