The World Health Organization (WHO) called on governments to categorize electronic cigarettes in line with tobacco products and to enforce a ban on all flavors. This move poses a challenge to cigarette companies' investments in smoking alternatives.

Citing studies, it said there was insufficient evidence that vapes helped smokers quit, that they were harmful to health, and that they could drive nicotine addiction among non-smokers, especially children and young people.

More 13-15 year olds are using vapes than adults in all WHO regions helped by aggressive marketing, it continued.

"Kids are being recruited and trapped at an early age to use e-cigarettes and may get hooked to nicotine," said Tedros Adhanom Ghebreyesus, WHO Director-General, urging countries to implement strict measures.

The WHO called for changes, including bans on all flavoring agents like menthol, and the application of tobacco control measures to vapes. Those include high taxes and bans on use in public places.

The WHO has no authority over national regulations and only provides guidance. But its recommendations are often adopted voluntarily.

The WHO and some other anti-tobacco organizations are pushing for stricter regulations on newer nicotine products, aiming for the alternatives on which some cigarette giants like Philip Morris International and British American Tobacco are basing their future strategies.

Major tobacco companies are hoping to build new revenue streams from cigarette alternatives as ever-stricter rules and falling smoking rates squeeze their traditional businesses in some markets.

The industry says vapes pose significantly lower health risks than tobacco and can help reduce its harms, with some flavors and lower prices important to encouraging smokers to switch – a position shared by some tobacco control advocates.

The WHO said vapes generate substances, some of which are known to cause cancer and pose risks to heart and lung health. They can also harm brain development in young people, it said, citing studies.

Some researchers, campaigners and governments see e-cigarettes, or vapes, as a key tool in reducing the death and disease caused by smoking. But the U.N. agency said "urgent measures" were needed to control them.