Background:
Little is known about the harmfulness perceptions of e-cigarettes (ECs) outside of high-income countries. This study examined reasons for EC use and harmfulness perceptions of ECs compared to regular cigarettes among smokers in Brazil, where 18.3% of smokers and 2.2% of non-smokers have tried ECs.

Methods:
Data were from Waves 2 (2012-13) and 3 (2016-17) of the International Tobacco Control (ITC) Brazil Survey, a cohort survey of 1200 adult smokers and 600 non-smokers in Rio de Janeiro, São Paulo, and Porto Alegre. At Wave 3, EC users (those who used ECs daily, weekly, monthly, and less than monthly; total n=48) were asked why they started and reasons for using ECs. At Waves 2 and 3, smokers who had ever heard of ECs (N=392 at Wave 2; N=859 at Wave 3) were asked whether they thought ECs are more, less, or equally harmful as regular cigarettes.

Results:
Among the 43 smokers who reported using ECs, the most common reasons for using e-cigarettes were: “using ECs is less harmful than smoking to other people” (69.3%), “out of curiosity” (59.4%), “they may not be as bad for your health” (59.0%), and “as a way to help you quit” (57.5%). Between 2012-13 and 2016-17, the percentage of smokers who “don't know” about the relative harmfulness of ECs decreased (41.6% to 28.0%; p< .001) and the percentage who believed that ECs are equally or more harmful than cigarettes increased (22.7% to 35.2%; p< .001).

Conclusions:
Smokers using ECs most commonly use ECs to reduce harm to others, reduce harm to their own health, and to help them to quit smoking. More smokers now have an opinion about the relative harmfulness of ECs, and a greater percentage of smokers now incorrectly believe that ECs are equally or more harmful than cigarettes.