Table 1

Study characteristics of included studies

First author/year	Country	Sample size	Vapers/dual users; recruitment age	Gender (% males)	Age mean (SD)	Intervention	Intervention duration	Control	Outcome measure	Follow-ups	Main outcome
Graham, 202139	USA	2588	Vapers; 18–24 years	48.4	20.4 (1.7)	Digital intervention: mobile phone text messaging	6 months	No intervention	Self-reported	1 and 7 months	↑30-day PPA ↑7-day PPA
Martinez, 202141	USA	2896	Vapers/dual users; >18 years	63.0	29.9 (11.2)	Education: (1) Information booklets about smoking (generic) and (2) Information booklets targeted at dual users	18 months	No intervention	Self-reported	1, 3, 6, 9, 12, 15 and 18 months	↑7-day PPA
Sahr, 202144	USA	24	Vapers; 18–24 years	70.8	20.5 (4.6)	Pharmacological and counselling: (1) NRT with behavioural support (2) vaping taper with behavioural support	6 months	Self-guided quit controls	Self-reported	1, 2, 3, and 6 months	↔CAR
Palmer, 202243	USA	27	Vapers; 17–21 years	33.3	20.3 (1.2)	Digital intervention: financial reward+telehealth (DynamiCare Health’s smartphone app)+contingency management	4 weeks	Monitoring control	Self-reported	1 and 2-months	↔30-day PPA
Caponnetto, 202338	Italy	140	Vapers; >18 years	49.0	52.6 (22.2)	Pharmacological and counselling: (1) varenicline and (2) vaping cessation counselling	12 weeks	Placebo treatment plus counselling	Cotinine-level-verified self-reported abstinence	1, 2, 3 and 6 months	↑7-day PPA ↑CAR
Palmer, 202342	USA	30	Vapers/dual users; >18 years	50	32.1 (10.9)	Pharcacological and counselling: (1) NRT, (2) support booklet and (3) text messaging	28 days	No intervention	Self-reported	1 and 2 months	↔7-day PPA
Krishnan, 202340	USA	58	Vapers; >18 years	53.5	27.3 (5.5)	Digital Intervention: Mobile phone text messaging	1 month	No intervention	Self-reported	1 month	↔7-day PPA

CAR, continuous abstinence rate; NRT, nicotine replacement therapy; PPA, point prevalence abstinence.