WHO estimates at least 15 million teenagers use e cigarettes worldwide Reuters 5 Vaping Facts You Need to Know Johns Hopkins Medicine E cigarette Use Persists Among Youth, New Data Shows Health Matters NYP Many Young Adults Who Began Vaping as Teens Can't Shake the Habit KFF Health News Teenagers who vape sweet flavoured e cigarettes more likely to stick with habit, study claims The Independent The Independent High Nicotine Vapes Don't Increase Nicotine Use Compared With Smoking, Study Finds