TY - JOUR PB - BMJ UR - https://doi.org/10.1136/bmj-2022-070351 N2 - OBJECTIVE: To quantify the effects of a series of text messages (safetxt) delivered in the community on incidence of chlamydia and gonorrhoea reinfection at one year in people aged 16-24 years. DESIGN: Parallel group randomised controlled trial. SETTING: 92 sexual health clinics in the United Kingdom. PARTICIPANTS: 92 sexual health clinics in the United Kingdom. INTERVENTIONS: 3123 participants assigned to the safetxt intervention received a series of text messages to improve sex behaviours: four texts daily for days 1-3, one or two daily for days 4-28, two or three weekly for month 2, and 2-5 monthly for months 3-12. 3125 control participants received a monthly text message for one year asking for any change to postal or email address. It was hypothesised that safetxt would reduce the risk of chlamydia and gonorrhoea reinfection at one?year by improving three key safer sex behaviours: partner notification at one month, condom use, and sexually transmitted infection testing before unprotected sex with a new partner. Care providers and outcome assessors were blind to allocation. MAIN OUTCOMES MEASURES: The primary outcome was the cumulative incidence of chlamydia or gonorrhoea reinfection at one year, assessed by nucleic acid amplification tests. Safety outcomes were self-reported road traffic incidents and partner violence. All analyses were by intention to treat. RESULTS: 6248 of 20?476 people assessed for eligibility between 1 April 2016 and 23 November 2018 were randomised. Primary outcome data were available for 4675/6248 (74.8%). At one year, the cumulative incidence of chlamydia or gonorrhoea reinfection was 22.2% (693/3123) in the safetxt arm versus 20.3% (633/3125) in the control arm (odds ratio 1.13, 95% confidence interval 0.98 to 1.31). The number needed to harm was 64 (95% confidence interval number needed to benefit 334 to ? to number needed to harm 24) The risk of road traffic incidents and partner violence was similar between the groups. CONCLUSIONS: The safetxt intervention did not reduce chlamydia and gonorrhoea reinfections at one year in people aged 16-24 years. More reinfections occurred in the safetxt group. The results highlight the need for rigorous evaluation of health communication interventions. TRIAL REGISTRATION: ISRCTN registry ISRCTN64390461. ID - discovery10156448 A1 - Free, Caroline A1 - Palmer, Melissa J A1 - McCarthy, Ona L A1 - Jerome, Lauren A1 - Berendes, Sima A1 - Knight, Megan A1 - Carpenter, James R A1 - Morris, Tim P A1 - Jamal, Zahra A1 - Dhaliwal, Farandeep A1 - French, Rebecca S A1 - Hickson, Ford Colin Ian A1 - Gubijev, Anasztazia A1 - Wellings, Kaye A1 - Baraitser, Paula A1 - Roberts, Ian A1 - Bailey, Julia V A1 - Clayton, Tim A1 - Devries, Karen A1 - Edwards, Phil A1 - Hart, Graham A1 - Michie, Susan A1 - Macgregor, Louis A1 - Turner, Katy ME A1 - Potter, Kimberley JF - BMJ Y1 - 2022/// AV - public VL - 378 TI - Effectiveness of a behavioural intervention delivered by text messages (safetxt) on sexually transmitted reinfections in people aged 16-24 years: randomised controlled trial N1 - © 2022 BMJ Publishing Group Ltd. This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license (http://creativecommons.org/licenses/by/4.0/). ER -