E-cigarette users have an increased susceptibility to the flu, COVID-19

Reviewed by Emily Henderson, B.Sc.November 18, 2020

In a controlled study of smokers, non-smokers, and e-cigarette users, researchers at the University of North Carolina School of Medicine found that e-cigarette users exhibited significantly altered immune responses to a influenza virus infection pattern, suggesting a increased susceptibility to the disease.

The results, published in American Journal of Respiratory Cell and Molecular Biology, show that vaping alters gene expression and protein production in respiratory cells, as well as altering the production of virus-specific antibodies.

In many of the study participants, we observed more changes in the immune response in e-cigarette users than we did in smokers.. “

Meghan Rebuli, PhD, First Author of the Study and Assistant Professor, Department of Pediatrics, University of North Carolina Health Center

Rebuli is also a member of the UNC Center for Environmental Medicine, Asthma, and Lung Biology.

“All of these factors have the potential to adversely affect virus response and post-infection immunity.

Although we used the flu as a model, this suggests that e-cigarette users are likely more susceptible to respiratory viruses than non-smokers, and this likely includes SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID -19). “

The main reason for avoiding smoking is the risk of cancer, heart disease, emphysema, stroke, diabetes, chronic obstructive pulmonary disease, and other lung diseases.

For these reasons, the researchers also studied the potential effects of e-cigarettes, which are made up of thousands of chemicals many of which are FDA-approved for ingestion, but not for inhalation.

But for many years, tobacco smoke inhalation has also been linked to an increased risk of viral infection, such as the flu. Inhalation of e-cigarette aerosols has also been linked to immune suppression within the respiratory tract, specifically the protective mucosal layer that lines the inside of the nasal cavity.

Rebuli, senior author Ilona Jaspers, PhD, and colleagues, thought that changes in the immune response of the nasal mucosa could modify the antiviral host defense responses in e-cigarette users.

This is important because viruses, including influenza and SARS-CoV-2, have been shown to infect nasal passages where they can replicate in cells, spread throughout the respiratory system, and be transmitted to other people.

Jaspers, the director of the UNC Center for Environmental Medicine, Asthma and Lung Biology, has conducted previous experiments showing that vaping has altered hundreds of genes in skin cells involved in the body’s natural immune defense.

For the current study, the researchers wanted to investigate what happens when e-cigarette users are exposed to a respiratory virus.

For the study, non-smokers, cigarette smokers, and e-cigarette users, aged 18 to 40, were inoculated with live attenuated influenza virus (LAIV) vaccine, a well-established pattern of influenza infection in the Jaspers laboratory, innate immune response.

Before and after inoculation, researchers collected nasal epithelial lining fluid, nasal wash fluid, nasal scraping biopsies, urine, and blood.

Scientists looked at cytokines and chemokines, influenza-specific immunoglobulin A (IgA), immune gene expression, and viral load markers.

The researchers found that although the amount of viral load markers did not differ between the three groups, the expected increases in anti-LAIV IgA nasal epithelial lining fluid – which is a potential indicator of post-infection developed immunity – did not occur. verified in e-cigarette users and cigarette smokers.

Additionally, LAIV-induced gene expression changes in nasal biopsies differed in cigarette smokers and e-cigarette users versus non-smokers, with more genes being modified in e-cigarette users, mainly resulting in decreased expression of immune genes critical for defense against viruses and immune memory generation.

“This is not good,” Jaspers said. “We want to see IgA levels rise during infection. It is the body’s natural way to defend itself against an invader. Here we have seen that both smoking and e-cigarette use hinder IgA levels. Expression suppressed as well. of important immune genes is of concern and in line with an overall suppression of appropriate immune responses. “

Additionally, an altered immune response in e-cigarette users and cigarette smokers could make vaccines less effective in these groups.

“We don’t know for sure if people who vape are more susceptible to COVID-19, or if vaccines would be less effective for them,” Rebuli said. “But we know we never want to see the suppression of genes, proteins and antibodies involved in our immune response. And this is what we see in our smoking and e-cigarette data.”