Those who smoke regularly are typically hit harder when a cold or flu virus strikes, but people who vape could also struggle to fight it, experts have warned.
Inhaling vapour from e-cigarettes can weaken the immune system and make the flu virus much more deadly, according to new research.
New findings from the American Thoracic Society revealed that inhaling vapour from e-cigarettes can change the cells in the respiratory tract, weakening the body's ability to fight off viruses - particularly the flu.
Researchers at the University of North Carolina conducted a study with three groups of volunteers, each separated into three categories - non-smokers, cigarette smokers and e-cigarette smokers.
From each participant, they collected fluid from the thin layer covering the respiratory tract and nasal passages, as well as nasal biopsies and blood.
All three groups were then given a weakened form of the flu virus, before the same samples were taken again at the end of the experiment.
Findings showed that specific proteins which are essential for fighting off viruses had noticeably diminished among e-cigarette smokers - and not among tobacco smokers.
Those who vape had lower levels of influenza-specific antibodies which protect against the virus, meaning their immune system was weakened.
Researchers concluded that the findings of the study suggest e-cigarette use, and smoking tobacco, both cause changes to the respiratory immune system. The significant reduction in specific antibodies among e-cigarette smokers means that the ability of the immune system to adapt to certain viruses could be impaired over time.