Background/Aim: There has been a rapid rise in vaping prevalence among youth and young adults in Great Britain since disposable vapes started to become popular in 2021. In January 2024, the government announced plans to introduce a number of new vaping policies, including a ban on disposable vapes, to tackle youth vaping. This study examined whether trends in current vaping and use of disposable vapes have changed since this announcement. Design, setting, and participants: Segmented regression analysis of data collected monthly between January 2022 and November 2024 as part of the Smoking Toolkit Study; a representative household survey in Great Britain. We ran generalised additive models using data from all participants aged 16+ (n=83,764; 'adults') and from a subset aged 16-24 (n=8,846; 'young adults'). Main outcome measures: Changes in trends in (i) the prevalence of current vaping and (ii) the proportion of vapers mainly using disposable devices. Results: Before January 2024, vaping prevalence was increasing by 24.5% per year (RRtrend=1.245 [95%CI 1.193-1.299]) and use of disposable vapes was increasing by 18.0% per year (RRtrend=1.180 [95%CI 1.106-1.258]). These trends changed after the new policy measures were announced (RR for change in trend=0.718 [0.623-0.827] and 0.558 [0.460-0.677], respectively). Instead of increasing, there was an uncertain decrease in vaping prevalence from 13.7% [12.7-14.7%] in January 2024 to 12.4% [11.4-13.6%] in November 2024) and a substantial decline in the proportion of vapers mainly using disposables from 43.7% [40.3-47.3%] to 30.8% [27.6-34.4%]. Similar changes were observed among young adults (vaping prevalence: RR for change in trend=0.647 [0.495-0.845]; use of disposable vapes: RR for change in trend=0.526 [0.400-0.693]), with an uncertain decline in vaping prevalence from 27.7% [24.5-31.3%] to 23.6% [20.2-27.6%] between January and November 2024 and the proportion of vapers mainly using disposables falling from 63.4% [59.0-68.2%] to 37.8% [32.3-44.2%]. Conclusions: Following the announcement of an impending ban on disposable vapes and other potential vaping policies, recent increases in vaping prevalence in Great Britain stalled - or may have even reversed - including among young adults. In addition, there was a shift away from using disposable vapes, with people increasingly opting to use devices that can be refilled and recharged.

JB has received unrestricted research funding from Pfizer and J&J, who manufacture smoking cessation medications. LS has received honoraria for talks, unrestricted research grants and travel expenses to attend meetings and workshops from manufactures of smoking cessation medications (Pfizer; J&J), and has acted as paid reviewer for grant awarding bodies and as a paid consultant for health care companies. All authors declare no financial links with tobacco companies, e-cigarette manufacturers, or their representatives.

This work was supported by Cancer Research UK (PRCRPG-Nov21\100002) and the UK Prevention Research Partnership (MR/S037519/1), which is funded by the British Heart Foundation, Cancer Research UK, Chief Scientist Office of the Scottish Government Health and Social Care Directorates, Engineering and Physical Sciences Research Council, Economic and Social Research Council, Health and Social Care Research and Development Division (Welsh Government), Medical Research Council, National Institute for Health Research, Natural Environment Research Council, Public Health Agency (Northern Ireland), The Health Foundation and Wellcome. For the purpose of Open Access, the author has applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission.

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Ethical approval for the STS was granted originally by the UCL Ethics Committee (ID 0498/001). The data are not collected by UCL and are anonymised when received by UCL.

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Data are available on Open Science Framework (https://osf.io/fsudk/).

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