Smoking increases the danger of respiratory infections, similar to colds, flu, pneumonia, and tuberculosis. Smoking can also contribute to coronavirus disease 2019 (COVID-19) complications.

Study: Tobacco product use and the risks of SARS-CoV-2 infection and COVID-19: current understanding and suggestions for future research. Image Credit: wavebreakmedia / Shutterstock.com

Background

Quite a few previous studies have confirmed the deleterious impact smoking has on the lungs. The harmful chemicals in tobacco smoke affect each the epithelium and vascular endothelium of the lungs.

More specifically, these substances appear to directly damage the epithelial cells, which subsequently impacts the epithelial barrier and mucociliary clearance. Along with these direct effects, these damaged cells release modified molecules into the lungs, which stimulate specific receptors that ultimately activate innate and purchased immune responses.

Despite the growing interest in determining the connection between smoking and COVID-19, the overwhelming caseload of COVID-19 patients has limited the power of researchers to dedicate time to this investigation. Nevertheless, a recent The Lancet Respiratory Medicine study examines the potential effects of tobacco use on severe acute respiratory virus coronavirus 2 (SARS-CoV-2) transmission, the pathophysiological changes as a consequence of tobacco use, in addition to the consequences of tobacco on immune and inflammatory responses to COVID-19.

Concerning the study

The target of the present study was to find out whether tobacco users have a greater preponderance of developing symptomatic SARS-CoV-2 infection, in addition to whether this patient population is at a better risk of severe COVID-19 or associated mortality, long COVID, or a distinct vaccination response.

The researchers analyzed the behavioral mechanisms related to tobacco consumption on COVID-19 and inflammatory immune responses. Moreover, additionally they screened risk aspects for the event of public health policies and patient care delivery.

To discover articles on COVID-19 and tobacco use, the researchers searched PubMed and Embase databases. Web of Science, PsycINFO, CINAHL, and Sociological Abstracts were also searched, while duplicates and opinion pieces were removed.

PubMed, Web of Science, Embase, CINAHL, PsychINFO, and Sociological Abstracts were searched again for articles on COVID-19 and tobacco use that were published between December 9, 2020, and August 30, 2021. Taken together, a complete of two,151 articles were chosen for review.

Study findings

Epidemiological studies investigating the impact of cigarette smoking on SARS-CoV-2 infection have rendered mixed results. Thus, further research is required to establish whether smoking or the usage of other tobacco products contributes to the susceptibility to COVID-19. 

It seems that smokers usually tend to suffer opposed outcomes related to COVID-19, including hospitalization and progression to severe disease. Tobacco use is related to COVID-19 severity; nevertheless, further studies are needed to elucidate whether nicotine and non-nicotine tobacco product ingredients contribute to disease susceptibility.

Upregulation of angiotensin-converting enzyme 2 (ACE2) receptors, immune suppression, oxidative stress, inflammation, and vascular injury may underlie the connection between cigarette smoking and severe COVID-19. Cigarette smoking increases the danger for long-term lung disease, heart problems, and diabetes, all of which increase the danger of severe COVID-19.

Tobacco products contain a big selection of probably toxic chemicals, while several harmful chemicals are also formed throughout the aerosolization process as a consequence of the heating or combustion of the product. Using tobacco products can lead to substantial damage; nevertheless, it stays unclear how individual chemicals and constituents contribute to those pathophysiological effects. 

Along with the impaired mucociliary clearance within the lungs, increased lung permeability, impaired immune function, higher expression of ACE2, cardiovascular dysfunction, in addition to viral infections, and severe diseases could also be more common amongst smokers. 

Through its activation of the cholinergic response, nicotine exerts an anti-inflammatory effect in several pathological conditions. Nevertheless, its role inside the context of the complex milieu of those conditions will not be well understood. Further, sharing of tobacco products increases SARS-CoV-2 transmission risk, as does passive smoking and inhalation of e-cigarette aerosols.

Conclusions

Smokers are more vulnerable to sustaining poor COVID-19 outcomes as in comparison with non-smokers. To higher shape public health recommendations and improve the care of people with a history of tobacco dependence, a more thorough understanding of tobacco use and disease risk is required.

It’s going to be imperative for future studies to acquire sufficient details about tobacco product use. Moreover, the event of a validated and harmonized approach to assessing the effect of tobacco use on COVID-19 susceptibility and disease severity, in addition to the danger of other infectious diseases, will even be crucial.

Journal reference:

• Benowitz, N., Goniewicz, M., Halpern-Felsher, B., et al. (2022). Tobacco product use and the risks of SARS-CoV-2 infection and COVID-19: current understanding and suggestions for future research. The Lancet Respiratory Medicine. doi:10.1016/s2213-2600(22)00182-5