An Intervention to Increase Condom Use Among Users of STI Self-Sampling Websites (Wrapped): Randomized Controlled Feasibility Trial (Preprint)
Authors: Newby Katie , Kwah Kayleigh , Schumacher Lauren , Crutzen Rik , Jackson Louise L , Bremner Stephen , Bailey Julia V , Brown Katherine E 
Published: January 2025

BACKGROUND

Sexually transmitted infections (STIs) such as chlamydia are common among young people and can lead to serious health issues if untreated. While condoms are recommended for prevention, many young people report inconsistent use during penetrative sex. Web-based STI testing is becoming increasingly popular, but these services typically offer minimal support or guidance on preventing future infections. The "Wrapped" intervention aims to help young users of web-based STI testing use condoms consistently and correctly during penetrative sex thus reducing future STI incidence.

OBJECTIVE

To assess whether and how it is possible to carry out a future Randomized Controlled Trial (RCT) of the Wrapped intervention.

METHODS

Users of web-based STI testing aged 16-24 years were randomised to an online, double-blind, two-arm, parallel group feasibility RCT (fRCT) in which Wrapped plus usual care (basic information on STIs and condom use) was tested against usual care alone. Main outcome measures were proportion of the sampling pool recruited and return of valid chlamydia self-sample at month (M)12. Other outcome measures included return of valid chlamydia self-sample at M3; completion of online surveys at baseline, M3, M6, and M12; follow-up by demographic characteristics; and acceptability of intervention and measures.

RESULTS

Over 31weeks, 173 participants were recruited and provided a baseline chlamydia test result, representing 1.5% of the sampling pool (n=11,413; 84 randomized to intervention, 89 to control). A valid chlamydia self-sample was returned by 75.7% (131/173; 95% CI: 68.6, 81.9) at M12. Based on this information, 3,574 participants, derived from a sampling pool of 238,266 service users, were estimated to be necessary to power a future full trial. Return of other follow-up measures: valid M3 chlamydia self-sample 75.1%, M3 survey 91.3%, M6 survey 90.8% and M12 survey 91.8%. Participants at M12 appeared to broadly represent individuals in the sampling pool with some exceptions; a tendency for over-representation of participants who were older (20-24 years), of Black ethnicity, and in the least deprived quintile; and for under-representation of participants who were younger (16-19 years), male, and in deprivation quintile three. There was some evidence that attrition was patterned by ethnicity and age in ways that compounded initial patterns of recruitment. Drop-out attrition was evident, with retention higher at M12 for the intervention group (85.7%) than the control group (66.3%). Eleven adverse events relating to participation were reported. A priori criteria for success were met.

CONCLUSIONS

A full trial is feasible. Although the recruitment rate was low, the high volume of young people using web-based STI testing services (approximately 585,000 annually based on the latest data) provides a sufficient pool to meet the required sample size. To ensure balanced representation, strategies to address potential under- and over-representation of certain demographic sub-groups by M12 should be implemented.

CLINICALTRIAL

Trial Registration: ISRCTN Registry ISRCTN17478654; http://www.isrctn.com/ISRCTN17478654

INTERNATIONAL REGISTERED REPORT

RR2-10.2196/43645