Mouse study shows that flavoured e-cigarette vapour has observed negative effects on lung function at least in the short term. Non-flavoured does not. Cigs are still worse in comparison. Need human trials for verification.

Health Headlines Commentary for October 12, 2018

Source:

E-cigarette flavourings may pose health risk, scientists warn as they call for tougher testing

Reference:

Comparison of the effects of e-cigarette vapor with cigarette smoke on lung function and inflammation in mice