American Thoracic Society International Conference
American Thoracic Society International Conference
May 21, 2019
2 min read

E-cigarettes may weaken immune system’s response to flu

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Photo of Meghan E. Rebuli
Meghan E. Rebuli

Research presented at the American Thoracic Society’s International Meeting suggests that although e-cigarettes and cigarettes can leave people susceptible to viral illness, the products affect the immune system differently. Researchers noted that e-cigarette use may specifically impair patients’ adaptive antiviral immune response.

“While both cigarette smoke and e-cigarette vapor are inhaled, there is some evidence that suggests the immune system responds differently to these products, but no one has looked at e-cigarettes and viral infection,” Meghan E. Rebuli, PhD, a Leon and Bertha Golberg Postdoctoral Fellow in toxicology and environmental medicine at the University of North Carolina at Chapel Hill, told Infectious Diseases in Children.

Using a live-attenuated influenza vaccine (LAIV), Rebuli and colleagues immunized volunteers who self-reported as nonsmokers, cigarette smokers and e-cigarette users. They analyzed patient samples of epithelial lining fluid, nasal lavage fluid, nasal biopsies and blood before and after vaccination.

The researchers observed varying responses to LAIV based on the volunteers’ smoking status. For example, in those who smoked, the researchers found increased influenza peptide cleavage activity, which was associated with increased viral microRNA levels after vaccination compared with nonsmokers.

Although this phenomenon was not observed among those who used e-cigarettes, Rebuli and colleagues found suppressed interferon-gamma (IFN-gamma) pathway genes and proteins needed for immune cell recruitment and antiviral responses in e-cigarette users but not in cigarette smokers. The researchers also observed suppressed IFN-gamma-inducible chemokines in nasal lavage fluid and epithelial lining fluid after vaccination with LAIV in e-cigarette users, and the IFN-gamma antiviral response remained suppressed after vaccination.

In addition, volunteers who used e-cigarettes had lower levels of influenza-specific immunoglobulin A compared with those who smoked cigarettes or did not smoke.

“Interestingly, we also found that the response in e-cigarette users is sex-specific,” Rebuli said. “The response in females was suggestive of immunosuppression, while in male e-cigarette users, changes in immune gene expression was a mixture of immune gene upregulation and down regulation. While we know that male and female immune systems function differently, especially in the context of respiratory virus infections, the opposing responses to viruses in male and female e-cigarette users were striking.”

Any dysregulation of a person’s immune response to pathogens has the potential to increase their susceptibility to infection.

“Therefore, our data is suggestive that e-cigarette users, especially female e-cigarette users, may experience increased risks of infection,” she added.

Rebuli said the key to addressing e-cigarette use is to make research findings understandable, especially to younger patients, allowing them to make informed decisions.

“For physicians, we suggest asking about e-cigarette use in a similar way to how they ask about cigarette and alcohol use, then providing easy-to-digest data about what is known on e-cigarettes and nicotine addiction,” she said. “Empowering patients to make informed decisions and having conversations about the risks of use will likely make a difference.” – by Katherine Bortz


Rebuli ME, et al. A4170/702. Presented at: ATS International Conference; May 17-22, 2019; Dallas.

Disclosure: Rebuli reports no relevant financial disclosures.