Asthma-causing bugs found in e-cigarettes for the first time

Henry Bodkin
This study is the first to find potentially harmful biological substances in e-cigarettes - Bloomberg News

E-cigarettes are contaminated with lung-damaging bacterial toxins of the type found in waste-incineration plants, scientists have discovered.

An investigation by Harvard University found that more than one in four of the increasingly popular products harboured bugs known to cause asthma, inflammation and reduced lung function.

In addition, the study revealed that sweet fruity flavours, which are particularly popular among teens, were most likely to carry the toxins.

Previous research has shown that chemicals linked to severe respiratory disease are found in common e-cigarette flavours.

However, this is the first time scientists have found potentially harmful biological substances in the devices.

Public Health England (PHE) campaigns strongly for cigarette smokers to switch to e-cigarettes, arguing the products are, at worse, only five per cent as harmful as traditional smoking.

This stance is coming under mounting criticism, however, from scientists who say it is too early to know the true dangers of vaping.

The Harvard team examined 75 popular e-cigarette products, namely single-use cartridges and e-liquids for refillable devices.

They found that 27 per cent contained traces of endotoxin, a microbial agent in agricultural and industrial settings, and that 81 per cent contained traces of glucan, which exist in the cell walls of most fungi.

Professor David Christiani, an environmental genetics expert and the study’s senior author, said: “Airborne Gram-negative bacterial endotoxin and fungal-derived glucans have been shown to cause acute and chronic respiratory effects in occupational and environmental settings.

“Finding these toxins in e-cigarette products adds to the growing concerns about the potential for adverse respiratory effects in users.”

Published in the journal Environmental Health Perspectives, the study found that cartridge samples had 3.2 times higher concentrations of glucan than the e-liquid samples.

Glucan concentrations were also significantly higher in tobacco and menthol-flavoured products than in fruit-flavoured products.

However, endotoxin concentrations were higher in fruit-flavoured products.

The research team said this indicates that raw materials used in the production of flavours may be a source of the microbial contamination.

They said the contamination of the products could have occurred at any point during the production process of either the ingredients or the final e-cigarette product.

But they believe that for e-cigarettes using single-use cartridges, the most likely source could the the cotton wicks, as both endotoxin and glucan are known contaminants of cotton fibres.

PHE figures show the number of UK children and teenagers trying vaping has doubled in recent years.

Approximatley 16 per cent of children aged 11 to 18 reported having tried vaping, according to 2018 data, a rise from 8.1 per cent in 2014.

The proportion who said they had never tried e-cigarettes fell from 91.5 per cent in 2014 to 83.4 per cent in 2018.

Last month a Daily Telegraph investigation revealed that Instagram is promoting vaping products to children as young as 13 using cartoons.

The Royal College of Paediatrics and Child Care Health has called for improved restrictions banning e-cigarette adverts from being targeted at minors.

Since 2016 it has been illegal to sell e-cigarettes to under 18s in the UK.

The Advertising Standards Authority says that vaping adverts must not be “directed at” or “likely to appeal” to people under 18 and should also avoid “reflecting or being associated with youth culture”.