Using electronic cigarettes (e-cigarettes) is likely to be considerably less harmful to health than continuing to smoke. However, we have insufficient evidence on any residual health harms associated with long term use, and the numbers of users that relapse to smoking, to make an estimate on the impact of their use on National Health Service costs.
The surveys that are undertaken often capture use at one point in time and we know that smokers often make repeated attempts to quit, using a variety of mechanisms to support them before success. E-cigarettes can help some smokers to quit for good and is currently the most popular quitting aid in England. Action for Smoking and Health data (May 2016) estimates that of the 2.8 million current users, around 1.3 million are ex-smokers, i.e. e-cigarette users who only vape. That is an increase from 2014 when around one third of users were ex-smokers.