It has become common to see children, some in their school uniforms, puffing on a vape.

The World Health Organisation points to the enticing flavours and targeted marketing to young people as the key reasons behind this trend.

In the US, e-cigarettes are the most commonly used tobacco product among middle and high school students aged 12 and older, with 5.9% of students reporting use.

Surveys from the UK indicate 20.5% of children (aged 11—17) have tried vaping, and that 7.6% of children vape. Similar usage rates ranging from 3.3% to 11.8% have been found in Southeast Asia. Evidence on vape use among adolescents living in Africa is more scarce.

We are public health researchers who have studied the phenomenon in South Africa. Our latest study, published in The Lancet’s eClinical Medicine, found that vaping among South African pupils is sky-high.

We surveyed more than 25,000 South African high school students across 52 schools in eight of South Africa’s nine provinces.

An estimated 16.8% of the sampled pupils use e-cigarettes.

Our findings show that high rates of adolescent vaping are not restricted to high-income countries.

Research has shown conclusively that children should not use these products because of the health risks.

In a 2016 report, the US surgeon-general called vaping among young people an “urgent public health problem”. One reason for this is that these products commonly deliver nicotine. Nicotine use during adolescence harms the developing brain, with potential long-term effects on learning, memory and attention.

Nicotine is also an addictive substance. Addictive behaviour in general is associated with the development of mental illness, further fuelling the mental health problems experienced by some adolescents. Substance abuse can lower their inhibitions, leading to increased high-risk behaviours.

Non-nicotine vapes are also bad for health. The chemical composition of specific flavours such as cherry, cinnamon and vanilla have also been shown to cause damage to the lung lining and blood vessels.

The rising popularity of e-cigarette use among adolescents globally should make helping young people with quitting vapes a priority.

We approached schools predominantly in major centres including Cape Town, Johannesburg, Pretoria and Durban. All were “fee-paying” schools. We were not able to include less well resourced schools without easy internet access or non-fee-paying schools.

We categorised the schools into three brackets:

About 17% of pupils in our sample attended lower-fee schools, 64% attended mid-fee schools, and 19% attended high-fee schools. About 31% of pupils attended co-ed schools, 41% attended all-boys’ schools, and 29% attended all-girls’ schools.

Students were asked about their use of four products in the 30 days preceding the survey: e-cigarettes, tobacco cigarettes, cannabis and hookah pipes.

Students who indicated they vaped were asked additional questions about their vaping history and habits. We also asked students about their reasons for starting and continuing to vape.

Using this data, we studied e-cigarette use, nicotine dependence, and the mental health and social stressors associated with vaping among a large sample of high school pupils.

Our study found 16.8% of high school pupils we surveyed were using e-cigarettes. There were far lower rates of tobacco cigarette use (2%), cannabis use (5%) and hookah pipe use (3%).

The proportion of pupils reporting e-cigarette use increased by grade: about 9% of grade 8 students reported using vapes, but this rose sharply to an average of 29.5% among grade 12 pupils (who will turn 18 in their final school year). Some schools had usage rates as high as 46% among grade 12 pupils.

Among the pupils who indicated they vaped, 38% vaped daily, and more than half of the pupils in our sample reported they vaped four or more days per week.

About 88% of pupils reported using vapes that contained nicotine. About 47% reported they vaped within the first hour of waking up — this is highly suggestive of nicotine addiction. We estimate that up to 61% of high school pupils who vape could be seriously addicted to nicotine.

We found the primary reasons for starting vaping differed from the main reasons for continuing to vape.

Just over half (50.6%) of the students who vaped cited social influences (family, friends, peer pressure, the need to fit in) as reasons for starting. About 20% of pupils indicated they had started vaping to cope with stress and anxiety, while 16.2% said they had started out of general curiosity.

Common reasons cited for continuing their vape use were to cope with anxiety, depression or stress (28.4%), or because they were addicted (14.9%).

Some pupils explicitly stated addiction in their reasoning: "It’s an addiction, no matter what I try I can’t stop." (female, 17)

Others described it more as a habit: "It has become a habit. I have to consume something constantly." (female, 18)

Less than 10% of students identified social influences as the reason they continued to vape.

About 46% of students did not list addiction as a reason for continuing to vape, though their reported vaping habits aligned with patterns typically seen in individuals who are highly addicted. This suggests that many pupils in our sample may lack awareness of what constitutes addiction.

Our research underscores the urgent need for a co-ordinated public health response to address the vaping crisis among high school pupils.

The government must pass the Tobacco Products and Electronic Delivery Systems Control Bill. This legislation will ensure vapes cannot be sold near schools or online.

The restrictions on the advertising of vaping products provided for in the bill may aid with this as well as the deglamorisation of vaping among young people — reducing the general curiosity that leads many young people to begin in the first place.

The dangerous myth that “vaping is safe” also needs to be debunked.

We need to help addicted teenagers to stop vaping. However, punishing students for vaping is unlikely to be an effective strategy.

Parents must be more aware of the signs of vaping and the underlying issues driving it. Health-care professionals should ask young people about their vape use during routine check-ups and school counsellors should teach coping strategies to help teens navigate life’s challenges.

• Sam Filby is a research officer at the Research Unit on the Economics of Excisable Products, University of Cape Town.

• Richard van Zyl Smit is an associate professor and consultant pulmonologist at the University of Cape Town.

This article was first published in The Conversation