New Australian research published this morning says flavoured e-cigarettes can kill lung cells.
The study's lead researcher, Miranda Ween from the School of Medicine at Adelaide University, told RNZ the study was investigating whether or not the same flavour, (apple was used for the research), bought from different suppliers could have different effects.
"What we found was that each of the flavours actually had very different chemicals in it and that they were all capable of killing airway cells and affecting immune cells even when there wasn't any nicotine in it."
Some of the damage to lung cells can be repaired by the body but it also introduces the possibility there would be errors in the repair process, Ween said.
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The research was a first step and the next stage for her team would be to isolate which particular chemicals are causing harm.
In light of the research becoming available, governments will be interested in regulation, she said.
The United States - where the deaths of several people are being attributed to vaping - is looking at restricting certain flavours in e-cigarettes and the rest of the world will be watching what happens and may look at following suit, she said.
New Zealand's director-general of health, Dr Ashley Bloomfield, said last week the government is preparing a bill on vape regulation, which will limit flavours to tobacco, menthol and mint.
It was possible safer vapes could be developed in the future but it would take a lot of research to achieve this, Ween said.
Most of the data on vaping, including theirs, showed vaping was probably less dangerous than smoking but most are short-term studies so the long-term effects aren't understood.
If e-cigarettes were used by former smokers in the short-term they would probably be safe but the goal was to give up altogether.
Ween said people who are trying to quit smoking should stick to traditional nicotine replacement therapies.