BACKGROUND AND AIMS Vaping products are diverse with a wide variety of features, and popular products change rapidly. This study examined the features and types of vaping products that people who smoke and/or vape perceive contribute to the health harms of vaping.

DESIGN, SETTING AND PARTICIPANTS This was a cross-sectional survey co-designed with adults who smoked/vaped and pre-registered. An on-line survey (November 2022) was used of a convenience sample of adults in the United Kingdom who smoked and/or vaped (n = 494).

MEASUREMENTS As primary outcomes, respondents were asked to select any of 15 vaping product features they perceived might have any effect on the health harms of vaping (for each: selected, not selected). Independent variables were smoking/vaping status (smoke and vape; vape, formerly smoked; vape, never regularly smoked; smoke, do not currently vape); relative vaping harm perceptions [less harmful than smoking (accurate), equally/more harmful than smoking or do not know/refused (other)]. Binary logistic regressions were used to compare outcomes by current vaping/smoking status and relative harm perceptions, adjusting for age and sex.

FINDINGS Most people (54.7%) selected between one and three features. The most frequently selected were nicotine concentration (62.2%) and amount of e-liquid consumed (59.1%), followed by nicotine type (e.g. salt or freebase; 33.0%), source/purchase location (25.3%), flavours (24.7%), temperature to heat e-liquid (21.1%), heat produced by device (20.9%), e-liquid brand (20.9%), amount of emissions (18.6%), device type (e.g. disposable, pod, tank; 17.2%), material of tank (17.0%), power/wattage (13.0%), device brand (8.1%), device size (4.1%) and device weight (2.4%). Higher nicotine concentrations, more e-liquid and salt (versus freebase) nicotine were perceived to confer greater harms. Disposables were perceived as slightly more harmful than reusable devices. There were few differences by current vaping/smoking status and between those with accurate (versus other) harm perceptions of vaping relative to smoking (P > 0.05 for most contrasts, adjusting for age and sex).

CONCLUSIONS Certain features and types of vaping products [higher nicotine concentrations, more e-liquid consumed and salt (versus freebase) nicotine] were perceived to confer greater health harms among a sample of UK adults who smoked and/or vaped. Findings are consistent with pervasive misperceptions that nicotine is a major cause of harm, although e-liquid volume is likely to contribute to harms.