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expert reaction to study looking at e-cigarette vapour and a molecule produced by cells that can be implicated in bacterial infections such as pneumonia

A new study, published in the European Respiratory Journal, explores the association between e-cigarette vapour exposure and the susceptibility of cells to bacterial infection.


Prof. Peter Hajek, Director of the Tobacco Dependence Research Unit, QMUL, said:

“It is a shame that the study did not compare the cellular effects with effects of smoking.  Effects of e-cigarette aerosol were compared with effects of clean air, but smoking is the more important comparator.  It is not clear though if there is any cause for alarm in these findings, whatever the comparator.

“The most relevant part of the paper concerns cells taken from people who do not smoke or vape and from vapers before and after vaping.  Here, there was no difference in PARF expression between vapers and non-vapers in the main samples!  The study only noticed a transient acute effect after vaping and it is not clear how this may translate into any health effects.

“Data from people, as opposed to cells and animals that are exposed in very different ways, show no sign that vaping makes vapers more vulnerable to infection.  They actually point in the opposite direction – previous work suggests smokers who switched from smoking to vaping report no increase, but in fact a significant decrease in respiratory infections1.”

1 ‘Changes in the Frequency of Airway Infections in Smokers Who Switched To Vaping: Results of an Online Survey’ by Joanna Astrid Miler, Bernhard Mayer and Peter Hajek, Journal of Addiction Research & Therapy, 2016, DOI: 10.4172/2155-6105.1000290


Prof. Peter Openshaw, Professor of Experimental Medicine, Imperial College London, said:

“The results from this study in cells grown in the lab and in mice suggest that vaping might make the cells lining the airways stickier and therefore more susceptible to bacterial colonisation, but the evidence that vaping might increase the risk of lung infection in people is only indirect.  Although it is possible that vaping might increase susceptibility to pneumonia, the effect is likely to be lower than from smoking itself.  We need further research to determine the effect of vaping on susceptibility to pneumonia in comparison to smokers. This might be supported by research studies of volunteers who vape, smoke or do neither, and are exposed to pneumococcal bacteria. This study should not be used as a reason to continue to smoke rather than vape – the evidence to date is that E-cigarettes are far less harmful than smoking.”


* ‘E-cigarette vapour enhances pneumococcal adherence to airway epithelial cells’ by Lisa Miyashita et al. published in the European Respiratory Journal on Thursday 8 February 2018.


Declared interests

Prof. Peter Openshaw: “Prof Openshaw is the Director of HIC-Vac, an MRC-funded human infection challenge network.”

None others received.

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