Researchers at the University of North Carolina at Chapel Hill have found that people who use e-cigarettes have significantly altered immune responses to influenza viruses – a worrying discovery as flu season approaches and COVID-19 surges across the United States – writes Zachery Eanes for The News & Observer.
E-cigarettes have boomed in popularity across the US in the past decade, even as the use of traditional cigarettes declined. The rise has been especially pronounced among youth.
Because of that, researchers have been focusing more attention on the potential health risks of e-cigarettes. Their latest study was published recently in the American Journal of Respiratory Cell and Molecular Biology.
“There’s been a lot of questions in the field as to whether e-cigarette and cigarette use is beneficial or damaging or problematic in terms of COVID, and we really haven’t had a good answer,” Meghan Rebuli, assistant professor in the University of North Carolina (UNC) Department of Pediatrics, said in an interview with The News & Observer, published on 13 November 2020.
But when compared to non-users, people who vaped e-cigarettes showed more changes in the immune genes in their respiratory cells that fight off viruses. They also showed a suppressed level of antibodies.
In many of the study’s participants, this change was even more pronounced among e-cigarette users than among smokers. The study compared e-cigarette users to cigarette smokers and non-smokers.
And while the study focused on a flu model, the findings suggest that e-cigarette users are likely more susceptible to respiratory viruses like COVID-19 than non-smokers, Rebuli said.
“We don’t want to see any suppression of genes, proteins and antibodies involved in an immune response,” she said. But that is exactly what they saw among those smoking both traditional and electronic cigarettes, reports The News & Observer.
“E-cigarette use is not safe or safer than cigarettes, and that is a really important take-home message,” Rebuli said. “You probably shouldn’t be inhaling any kind of tobacco-related products; it all impairs your immune response to the viruses.”
Rebuli added that if you do smoke or vape: “You need to be hyper vigilant about using PPE and protecting yourself from COVID and from respiratory viral infections, because you may be more susceptible to adverse responses to these viruses.”
The study compared non-smokers, cigarette smokers and e-cigarette users between the ages of 18 and 40, The News & Observer reported. The researchers inoculated participants with a live attenuated influenza virus, a modelled flu infection that allows researchers to safely examine immune responses in subjects.
After comparing the nasal fluid and other biomarkers of the patients, the researchers did not find that the viral load, or the amount of the virus in a person, differed among the three groups in the study.
But they did find a decreased expression of immune genes critical for defence against a virus as well as the genes that help train the body to prevent reinfection.
“This is not good,” Ilona Jaspers, the director of the UNC Center for Environmental Medicine, Asthma, and Lung Biology, said in a statement. “We want to see [these] levels increase during infection,” she added. “It’s the body’s natural way to defend against an invader. Here we saw that both smoking and e-cigarette use hampers [immune gene] levels.”
According to The News & Observer, Rebuli said this could be worrisome news for vaccine effectiveness among this population as well. The question, she said, “is if this is a 90% effective vaccine, is it going to be similarly effective in e-cig users, or are they going to have trouble generating that immune memory?”
That is still unclear, Rebuli said. Further studies are needed that look at COVID-19 specifically.
E-cigarette Use Alters Nasal Mucosal Immune Response to Live-Attenuated Influenza Virus (LAIV)
American Journal of Respiratory Cell and Molecular Biology. Published on 23 October 2020.
Meghan E Rebuli, Ellen Glista-Baker, Jessica R Hoffman, Parker F Duffney, Carole Robinette, Adam M Speen, Erica A Pawlak, Radhika Dhingra, Terry L Noah and Ilona Jaspers
Inhalation of tobacco smoke has been linked to increased risk of viral infection, such as influenza. Inhalation of e-cigarettes aerosol has also recently been linked to immune suppression within the respiratory tract, specifically the nasal mucosa.
We propose that changes in the nasal mucosal immune response modify antiviral host defense responses in e-cigarette users.
Non-smokers, cigarette smokers, and e-cigarette users were inoculated with live attenuated influenza virus (LAIV) to safely examine innate immune response to influenza infection. Pre- and post-LAIV inoculation, we collected nasal epithelial lining fluid (NELF), nasal lavage fluid (NLF), nasal scrape biopsies, urine, and blood.
Endpoints examined include cytokines/chemokines, influenza-specific IgA, immune gene expression, and markers of viral load. Statistical analysis included primary comparisons of cigarette and e-cigarette groups to non-smokers, as well as secondary analysis of demographic factors as potential modifiers.
Markers of viral load did not differ among the three groups. NLF anti-LAIV IgA levels increased in non-smokers post-LAIV, but not in e-cigarette users and cigarette smokers. LAIV-induced gene expression changes in nasal biopsies differed in cigarette smokers and e-cigarette users as compared to non-smokers, with a greater number of genes changed in e-cigarette users, mostly resulting in decreased expression.
The top downregulated genes in cigarette smokers were: SMPD3, NOS2A, and KLRB1, and e-cigarette users: MR1, NT5E, and HRAS.
Similarly, LAIV-induced cytokine levels in NELF differed among the three groups including decreased antiviral host defense mediators: IFNγ, IL6, and IL12p40. We also detected that sex interacted with tobacco product exposure to modify LAIV-induced immune gene expression.
Our results demonstrate that e-cigarette use altered nasal LAIV-induced immune responses, including gene expression, cytokine and chemokine release, and LAIV-specific IgA levels. Together, these data suggest that e-cigarette use induces changes in the nasal mucosa consistent with the potential for altered respiratory antiviral host defense function.
The News & Observer story – E-cigarettes can significantly alter a body’s response to viruses, UNC study finds
American Journal of Respiratory Cell and Molecular Biology – E-cigarette Use Alters Nasal Mucosal Immune Response to Live-Attenuated Influenza Virus (LAIV)