The pervasive misperception that e-cigarettes are equally or more harmful than combustible cigarettes is a barrier to current smokers switching to e-cigarettes. To tackle misperceptions, public health bodies are using informational videos, although their efficacy is unknown. In our online study, current UK smokers who do not vape (n = 382) were randomized to view either: (1) a Cancer Research UK (CRUK) text-only video; (2) a video featuring leading e-cigarette experts (expert); or (3) a no video control condition, and then completed questions regarding e-cigarette harm perceptions. Compared to the control condition, participants in the CRUK condition, and especially those in the expert condition had more accurate harm perceptions of e-cigarettes and had more accurate knowledge of e-cigarette constituents. In the expert condition, 67% of individuals reported they would try an e-cigarette in a future quit attempt, compared with 51% in the CRUK condition and 35% in the control condition. Our findings are encouraging in the face of mounting evidence that e-cigarette misperceptions are increasing. Whilst misperceptions are often characterized as resistant to correction, we find that carefully designed public health information videos have the potential to promote a more accurate, informed view of e-cigarettes, and encourage intended e-cigarette use among UK smokers. Importantly, we find this among current smokers who do not vape, a group often reported as having the highest levels of misperceptions and as having the most to gain from accurate e-cigarette perceptions. There is mounting evidence that e-cigarette misperceptions are increasing, particularly among smokers who do not vape, a group who have most to gain from accurate information about e-cigarettes. Misperceptions are often characterized as difficult to change and there is relatively little research on how to correct e-cigarette misperceptions. Our research in the UK shows that, compared to controls, e-cigarette misperceptions can be corrected among those smokers who are shown carefully constructed expert videos. This work has important implications for the development and dissemination of these important messages.The overarching objective of this project is to establish a theoretically-driven and empirically-supported evidence base to guide the development of tobacco health warnings by national and international policymakers. Ultimately, through the provision of evidence-based health warnings on tobacco packaging, this research will improve population health by encouraging smoking cessation among adults and preventing smoking uptake among adolescents.

We conducted an online between-subjects experimental study in February 2020 with UK smokers who do not use e-cigarettes (i.e., do not vape). Participants were randomized into one of the three conditions: CRUK video; expert video; or a no message control. Harm perceptions were the primary outcome measure. We published the study protocol on the Open Science Framework prior to starting testing and this includes more information about the study methods and the analysis plan (https://osf.io/ja34v/). Our pre-planned sample size calculation indicated that we needed 390 participants to observe a small effect size (f = 0.20) with 95% power and an alpha level of 5%. Further details are in the pre-registered protocol. We recruited an equal number of female and male participants opportunistically through Prolific, an online crowdsourcing platform. To be eligible for inclusion, participants were at least 18 years of age, lived in the UK and self-reported that they smoked daily, and did not vape (classified as using an e-cigarette less than monthly). Participants were reimbursed 13p for completing a short prescreening survey. Eligible participants were invited to participate in the main, 10 min experiment on Qualtrics for which they were reimbursed £1.30. The study was approved by the Faculty of Science Research Ethics Committee at the University of Bristol (reference: 23051753685).