Point of Sale Scanner Data for Rapid Surveillance of the E-cigarette Market.

Market-leading e-cigarette brands changed substantially in Nielsen channels from 2013 to 2015. Brand leaders in these channels are now owned by tobacco companies. Changes in labelled nicotine content and fruit-flavored products and product types suggest that as e-cigarette use increases, convenience store and mass market channels are offering new products to meet consumer preferences; however, Nielsen channels do not represent the entire e-cigarette marketplace.