Longitudinal Effects of a Smartphone Game (Tumaini) to Prevent HIV among Young Africans: 45-Month Trajectories of Proximal Outcomes related to Condom Use in a Randomized Controlled Trial (Preprint)

BACKGROUND African adolescents and young adults account for a disproportionate number of new HIV infections. There is an urgent need to identify scalable and cost-effective behavioral HIV prevention strategies for this population. Using a condom at first sex is associated with higher likelihood of consistent use later. Tumaini (“Hope for the Future” in Swahili) is a choose-your-own-adventure smartphone game that has been shown to reduce risk of unprotected first sex by endline in a 45-month randomized controlled trial in Western Kenya. OBJECTIVE We sought to assess the impact of Tumaini on proximal outcomes related to condom use at first sex, specifically, behavioral intentions, self-efficacy, attitudes, and knowledge, longitudinally across mid-adolescence in the above trial. METHODS Adolescent participants (n=996, mean baseline age 14.0 years) were randomized 1:1 to receive either a smartphone loaded with Tumaini or an attention-control Math game for 5-7 weeks at three timepoints (mean ages 14.0, 15.3, and 16.0 years). They completed a behavioral survey at 13 timepoints through mean age 17.7 years. Using generalized estimating equations and controlling for age at baseline, we modeled mean scores (overall and stratified by gender) on a range of condom-related survey items over time to assess mean differences at specific timepoints. We applied appropriate Bonferroni corrections (α= 0.05/4 and α= 0.05/12) to inferences about cross-arm differences in mean changes relative to baseline at four time points (after each intervention period and at endline) and within-arm mean changes relative to baseline at each of the 12 post-baseline timepoints. Analyses were conducted as intent-to-treat. RESULTS At endline, 97.8% of the sample (n=974) had been retained. Participants in both arms dedicated a mean total >30 hours to their assigned game. There was significant improvement across all condom-related proximal outcomes in the intervention arm relative to the control arm immediately after initial intervention exposure. For almost all outcomes, a significant cross-arm difference was also present at endline, and for most outcomes at the two intervening comparison timepoints. Some outcomes saw stronger intervention effects on female participants (e.g., self-efficacy to refuse unprotected sex) or male participants (e.g., knowledge that condoms are an effective way to prevent HIV). In each arm, intention to use a condom at first sex was consistently higher among male participants; however, female intervention-arm scores overtook male control-arm scores following initial intervention exposure. CONCLUSIONS Tumaini significantly improved theory-based proximal outcomes related to condom use, with effects sustained 45 months post-initial exposure and 16 months post-most recent exposure. Adolescents benefited from even short-term exposure, though repeated exposure generally sustained and reinforced intervention effects. In the context of increasing access to smartphones, Tumaini has potential for high scalability and impact on condom-related outcomes. CLINICALTRIAL ClinicalTrials.gov, NCT04437667