Does vaping raise the risk of spreading Covid-19?

A new analysis has suggested vaping only slightly raises the risk of a person infected with Covid-19 passing on the virus through the air. Photo / Stephen Parker

A new analysis has suggested normal vaping only slightly raises the risk of a person infected with Covid-19 passing on the virus through the air.

But an independent expert has cautioned that more evidence is needed to make that conclusion.

The link between Covid-19 and e-cigarette use has come under focus worldwide - especially in countries where the virus is spreading through communities.

One early US study found young people who vape or smoke have a higher chance of catching the virus, which could more easily infect lungs that were already damaged.

Those who had used cigarettes or e-cigarettes within the past 30 days were, on average, nearly seven times more likely to be diagnosed with Covid-19.

But there has been comparatively little research into the danger of vaping spreading the virus through droplets carried by exhaled e-cigarette aerosols.

Advice from Massachusetts General Hospital states there is a higher risk of this, given people who vape or smoke are more likely to spread Covid-19 through coughing, or having higher hand-to-mouth contact.

In a new "pre-print" paper published before peer-review, Dr Eliana Golberstein, a scientist with New Zealand-based vaping supplies company Myriad Pharmaceuticals, and fellow researchers in Italy and Mexico, modelled the flow of these aerosols and how they might carry coronavirus.

They looked at the risk from "low intensity" vaping - practised by about 80 to 90 per cent of vapers - which, with each puff, could send up to 230 respiratory submicron droplets 1 to 2m.

By contrast, "high intensity" vaping could carry hundreds, and up to 1000, droplets per puff, over more than 2m.

The researchers found that low intensity vaping from an infected person in an indoor space like a home or restaurant raised the risk of transmitting the virus by about 1 per cent.

The relative risk rose to five to 17 per cent with "high intensity" vaping.

But the threat from an infected person speaking or coughing was much higher still - increasing the risk by between 40 and 90 per cent, and more than 200 per cent, respectively, they found.

Golberstein and her colleagues further found that disinfectant properties of glycols in the exhaled vapour were unlikely to act efficiently on pathogens within it.

They concluded that vaping in houses or social spaces didn't require any extra special interventions above those already widely recommended: particularly social distancing and wearing face masks.

Golberstein pointed out that New Zealand - where an estimated 200,000 people use vaping products - already had restrictions in place.

Just-passed laws mean vaping is banned in buses, trains, taxis and rideshare services, along with passenger queuing areas and lounges, casinos, restaurants or licensed premises that aren't open areas.

Dr Michael Maze, an infectious disease and respiratory physician at Otago University, said the findings had to be treated with some caution, given the authors' stated involvement in the vaping industry, and the fact the paper was a pre-print.

Maze added there was also a lack of existing empirical evidence to underpin the findings.

"I'd be cautious about declaring there's minimal increased risk until we've seen more data from actual experiments using vaping, and performed by scientists who don't have conflicts."