Millions of people in the United States regularly use tobacco or nicotine products. It’s well known that smoking can have detrimental health effects, and has been linked to increased risk of cancer, heart and lung diseases, stroke, diabetes, and other problems. Smokeless tobacco products are also associated with cancer and other health risks. The health effects of e-cigarettes and vaping, which have risen in popularity in recent years, are less clear but not completely innocuous. Therefore, some may be wondering if their tobacco or nicotine use puts them at special risk during the COVID-19 pandemic. This piece will summarize speculation about the health effects of tobacco use and vaping in relation to COVID-19.

Currently, there is no direct evidence that smoking or vaping increases susceptibility to COVID-19. However, smokers are more likely to contract respiratory infections and have higher rates of influenza, tuberculosis, and pneumonia than non-smokers (Kaur, 2020). Additionally, while vaping was originally assumed to be less detrimental to lung health than smoking, a recent outbreak of life-threatening lung injuries and illnesses in mid-2019 raised concern about whether vaping is actually a safe smoking alternative (Krishnasamy). Given that smokers are susceptible to respiratory infections, it may be that COVID-19 symptoms could manifest more severely in patients with lungs previously damaged by smoking.

A possible molecular link between tobacco use and coronavirus susceptibility lies in angiotensin-converting enzyme II (ACE2) gene expression. SARS-CoV2, the virus that causes COVID-19, binds to and uses ACE2 as a site of host cell entry (Kaur, 2020). ACE2 expression may be upregulated in the small airway epithelial cells of smokers (Leung, 2020). This suggests that there could be more entry points for the coronavirus in the airways of smokers compared with non-smokers. As a result, smokers may be more susceptible to COVID-19 infection. Though it has not been tested, it is suggested that vaping may also increase ACE2 expression. Like smoking, vaping is known to stimulate nicotinic acetylcholine receptors, which are associated with ACE2 (Wang, 2020). Though the connection between ACE2 expression and increased COVID-19 susceptibility in smokers is still speculation, it offers a potential mechanism for unique risks in tobacco users facing COVID-19.

Tobacco users may also pose a greater risk of spreading COVID-19 to others. People who use smokeless tobacco products like chewing tobacco often spit a mixture of tobacco and saliva to avoid ingesting the tobacco. Because the saliva of a COVID-19 patient can be contaminated with SARS-CoV2, chewing tobacco in public could pose a risk of infecting others (Singh, 2020). Additionally, tobacco smokers tend to cough more than nonsmokers. Since COVID-19 can be transmitted through coughed aerosols, smokers with COVID-19 may spread the virus more readily than non-smokers. Finally, e-cigarettes could spread the coronavirus when they are shared between users. When an infected person uses an e-cigarette, droplets containing the virus could be present on the surface of the mouthpiece. Anyone who subsequently uses that e-cigarette could face a risk of infection. For these reasons, tobacco users with COVID-19 may infect others at a greater rate.

Though there is no definitive research, the medical community generally fears that the respiratory effects of smoking and vaping may dangerously intersect with COVID-19. It is possible that smoking-induced gene expression changes could make them more susceptible to infection, or that tobacco users may spread the virus to others at a higher rate. Whether or not these speculations are confirmed, it would likely be wise for tobacco users to consider these risks and exercise appropriate caution in effort to protect themselves and their communities.

Author: Cory Kittleman

Edited by Drs. Robert O. Messing and Emma Erickson

Photo by Markus Spiske on Unsplash

References

1. Kaur, G., Lungarella, G. & Rahman, I. SARS-CoV-2 COVID-19 susceptibility and lung inflammatory storm by smoking and vaping. J Inflamm 17, 21 (2020). https://journal-inflammation.biomedcentral.com/articles/10.1186/s12950-020-00250-8
2. Krishnasamy VP. Update: characteristics of a nationwide outbreak of e‐cigarette, or vaping, product use–associated lung injury—United States, August 2019–January 2020. MMWR Morb Mortal Wkly Rep. 2020;69(3):90–94.
3. Leung JM, Yang CX, Tam A, Shaipanich T, Hackett TL, Singhera GK, et al. ACE-2 expression in the small airway epithelia of smokers and COPD patients: implications for COVID-19. Eur Respir J. 2020;55(5):2000688.
4. Singh, AG, Chaturvedi, P. Tobacco use and vaping in the COVID‐19 era. Head & Neck. 2020; 42: 1240– 1242. https://onlinelibrary.wiley.com/doi/10.1002/hed.26208
5. Wang Q, Sundar I, Li D, Lucas J, Muthumalage T, McDonough S, Rahman I. E-cigarette-induced pulmonary inflammation and dysregulated repair are mediated by nAChR α7 Receptor: Role of nAChR α7 in ACE2 Covid-19 receptor regulation. Respiratory Res. 2020. https://www.researchsquare.com/article/rs-14392/v2. [Pre-print].