In Reply Dr Maziak’s concerns are understandable, and I share his commitment to protecting youth. However, they are not currently protected: 5.6 million children alive today are expected to die as a result of cigarette use, along with 480 000 adults annually.¹ Moving cigarette users to safer e-cigarettes benefits adults and youth.

There is little evidence that e-cigarettes are a gateway to cigarettes. A recent study suggested this possibility, but confused correlation with causation.² Youth e-cigarette experimentation (2.1% in 2012) is not associated with increased cigarette use.³ On the contrary, youth smoking declined 10% annually between 2010 and 2013 to record lows (9.6%).³ Longitudinal surveillance is required to prove a direct causal gateway connection.