The impact of financial incentives on HIV incidence among adolescent girls and young women in Eswatini: Sitakhela Likusasa, a cluster randomised trial

INTRODUCTION: Incentives conditional on school attendance or on remaining free of sexually transmitted infections have produced mixed results in reducing HIV incidence. METHODS: HIV-negative adolescent girls and young women aged 15–22%–50% of whom were out of school—were recruited from 293 clusters in Eswatini from urban (30%) and rural areas (70%). Financial incentives conditional on education attendance were randomly allocated at the cluster level. All participants were further individually randomised into eligibility for a raffle incentive conditional on random selection into the raffle, on negative tests for syphilis and Trichomonas vaginalis and on being a raffle winner, creating four subarms in a 2×2 factorial design: no-intervention, raffle incentive, education incentive and raffle & education incentive. Randomisation was unblinded to participants. Logistic regressions were used in intention-to-treat analysis of HIV incidence over 3 years to estimate the impact of incentives conditional on school attendance and raffle incentives conditional on remaining sexually transmitted infection free. RESULTS: The study recruited 4389 HIV-negative participants, who were distributed into four subarms: no intervention (n=1068), raffle incentive (n=1162), education incentive (n=1088) and raffle and education incentive (n=1071). At endline, 272 participants from 3772 for whom endline data were collected, tested positive for HIV. HIV incidence among participants in education treatment arm was significantly lower than in the education control arm, 6.34% (119/1878) versus 8.08% (153/1894) (p=0.041); OR: 0.766 (0.598 to 0.981); adjusted OR (aOR): 0.754 (0.585 to 0.972). Compared with the no intervention subarm, HIV incidence in the raffle and education incentive subarm was significantly lower, 5.79% (54/878) versus 8.84% (80/905); OR: 0.634 (0.443 to 0.907); aOR: 0.622 (0.433 to 0.893), while it was not significantly lower in the raffle incentive subarm. CONCLUSION: Financial incentives conditional on education participation significantly reduced HIV infection among adolescent girls and young women in Eswatini and appear to be a promising tool for prevention in high HIV prevalence settings. TRIAL REGISTRATION NUMBER: Western Institutional Review Board—protocol number 20 141 630. Eswatini National Health Research Review Board—FWA00026661. Pan African Clinical Trials Registry—PACTR201811609257043.