Six million people die every year as a result of tobacco smoking, according to an estimate by the World Health Organization. It is a number worth keeping in mind as the scientific disputes over electronic cigarettes continue to smoulder.

The US Food and Drug Administration last week announced a “historic rule” that gives it the right to regulate e-cigarettes — which vaporize nicotine — as it does tobacco products. Nearly all e-cigarettes will now have to go through an approval process, with sales to young people prohibited, and health warnings included on packaging and advertisements.

Sylvia Burwell, the US Secretary of Health and Human Services, noted that e-cigarette use is shooting up among young people in the United States, “creating a new generation of Americans who are at risk of addiction”, even as cigarette smoking continues to decline.

Some states are already ahead of federal law — earlier this month, California defined e-cigarettes as tobacco products, with all that that entails. The European Union is also set to take a tougher stance. An EU-wide directive that comes into force this year on tobacco products will control nicotine content.

These ‘vaping’ devices have split researchers. Some see a route to end the tobacco scourge. Conventional medicine provides few escapes from nicotine addiction, and the speed at which smokers embrace electronic systems seems to be a blessing. If the world’s smokers switched from burning to vaping, that figure of six million deaths would fall.

But other scientists see problems. They fear that electronic devices subvert the message that smoking is bad, and offer people a nicotine fix in places where cigarettes have long been excluded. They fear a new age of nicotine, and that the six-million figure will rise.

This difference of opinion has spilled messily over into the research arena. Published studies are ruthlessly spun or picked apart by opposing sides. Sometimes the fight happens even before publication, with journalists sent quotes under embargo that critique claims and conclusions before they are publicly available.

Both sides are acting in good faith, but their arguments and increasingly entrenched positions frequently generate more heat than light. To progress, researchers on both sides must establish what evidence should be gathered to answer the central question: how can e-cigarette use and regulation lead to the largest possible reduction in deaths from tobacco? As part of this process, they should identify key data that, if forthcoming, would change their current view.

There is good reason for researchers to come together on this, and quickly. Conventional tobacco firms are grabbing an increasingly large share of the e-cigarette market. This should concern everyone — and focus minds. Few industries have historically been quite so willing to dissemble, and to market products with so few benefits and so many harms.

Researchers should remain focused on the enemy that needs to be fought — the horrific harm caused by tobacco. Disputes are part of science. They must be conducted in the open, and no researcher — and no piece of research — can be immune from criticism. But the tobacco-science community must find a way forward. It is not hyperbole to say that millions of lives are at stake. Six million of them are, every year.