Critics claim these products are often marketed to children and adolescents by the tobacco-and-related industries that manufacture them, using thousands of appealing flavors and misleading claims about the products.
The WHO is concerned that children who use these products are up to three times more likely to use tobacco products in the future.
Earlier this month, research in medical journal The Lancet concluded that "there are concerns that the use of electronic nicotine delivery systems and electronic non-nicotine delivery systems in children and adolescents could potentially be harmful to health."
However, the report authors say there has been progress in the fight against the tobacco epidemic, with the increased adoption of WHO-recommended tobacco-control measures.
More than five times as many people are now covered by at least one WHO-recommended tobacco-control measure compared with 2007.
Some of the control measures the WHO uses to monitor tobacco use and act as a brake on people starting to light up are:
1. Protecting people from tobacco smoke 2. Offering help to quit 3. Warning about the dangers of tobacco 4. Enforcing bans on advertising, promotion and sponsorship 5. Raising taxes on tobacco
Some 5.3 billion people are now covered by at least one of these measures – 1 billion were covered in 2007.
Cigarette firm wants to stop smoking
The release of the report comes after the CEO of tobacco business Philip Morris International called on the UK government to ban cigarettes within a decade.
On Sunday, Jacek Olczak admitted that such a move that would outlaw his company's own Marlboro brand.
He said his company could "see the world without cigarettes … and actually, the sooner it happens, the better it is for everyone."
In May, Olczak said it is "totally uncharted territory – nobody ever tried to 'un-smoke' the world."
Smoking, including second-hand smoke, kills roughly 8 million people a year, according to the World Health Organization.