Vapour from e-cigarettes seems to help pneumonia-causing bacteria to stick to the cells that line the airway, say researchers

A study based on experiments with cells, mice and humans has found e-cigarette vapour has a similar effect to the reported effects of traditional cigarette smoke or particulate matter from pollution, both of which are known to increase susceptibility to lung infection with pneumococcal bacteria.

Lead researchers Jonathan Grigg, who is a Professor of Paediatric Respiratory and Environmental Medicine at Queen Mary University of London, says the study indicates that vaping – especially in the long term – could raise the risk of bacterial lung infection.

“Pneumococcal bacteria can exist in our airways without causing illness. However, in some cases, they can invade the lining cells causing pneumonia or septicaemia,” says Professor Grigg.

“We know that exposure to traditional cigarette smoke helps these bacteria stick to airway lining cells, increasing the risk of infection. We wanted to see whether or not e-cigarettes might have the same effect.”

The research examined the effects of e-cigarette vapour on a molecule produced by the cells that line the airway.

When researchers introduced pneumococcal bacteria to these cells, they found that exposure to either nicotine-containing or nicotine-free vapour doubled the amount of bacteria that stuck to airway cells.

A separate mouse study also found inhaled exposure to e-cigarette vapour increased the number of pneumococcal bacteria in the respiratory tract after infection, making mice more susceptible to disease.

Finally, the team study the cells lining the noses of 17 people.

Of these, 10 were regular users of nicotine-containing e-cigarettes, one used nicotine-free e-cigarettes, and six were not vapers.

One hour after vaping, levels of receptors that increase the ability of bacteria to stick to airway cells had increased three-fold.

“Together, these results suggest that vaping makes the airways more vulnerable to bacteria sticking to airway lining cells,” says Professor Grigg.

“If this occurs when a vaper gets exposed to the pneumococcal bacterium, this could increase the risk of infection.

“Some people may be vaping because they this it is totally safe, or in an attempt to quit smoking, but this study adds to growing evidence that inhaling vapour has the potential to cause adverse health effects.

“By contrast, other aids to quitting such as patches or gum do not result in airway cells being exposed to high concentrations of potentially toxic compounds,” he says.

The research was published in the European Respiratory Journal.