Background:
This paper compares beliefs about the relative harms of exposure to secondhand electronic cigarette (EC) vapor compared to cigarette smoke, rules about smoking and vaping in the home, and adherence to rules restricting vaping in public places in Australia (AU) and Canada (CA) which have generally more restrictive policies on the marketing of ECs compared to England (EN) and the United States (US) which have less restrictive policies.

Methods:
Data came from 12,411 adult (aged 18 years and older) current and former smokers and vapers who participated in the 2016 International Tobacco Control (ITC) Four Country Survey carried out in AU (n=1491), CA (n=3801), EN (n=4339) and US (n=2780). The web-based survey recruited participants from online panels in each country with selection criteria intended to generate representative samples of current and former smokers and vapers in each country.

Results:
The majority of respondents in each country believed that exposure to secondhand EC vapor was less dangerous compared to exposure to smoke. Across all countries vapers were more likely than non-vapers to believe that exposure to secondhand EC vapor was less dangerous compared to exposure to smoke. The overwhelming majority of respondents in all countries did not allow smoking in their home, while most allowed vaping. Rules about whether smoking was permitted inside the home were more permissive among smokers whereas rules about vaping were more permissive among vapers. Nearly all vapers reported that they do not vape in public places when it is prohibited.

Conclusions:
Being a vaper or smoker was more strongly associated than restrictiveness of EC regulations with beliefs about the dangers of secondhand EC vapor exposure, rules people have about allowing smoking and vaping in their homes, and adherence to rules restricting vaping in public places.