Abstract
OBJECTIVES: Participation in HIV prevention trials could trigger risk compensation among participants. We evaluated potential risk compensation following use of a vaginal ring microbicide by women in a phase III trial in southwestern Uganda. METHODS: We used markers of sexual risk behaviour documented on standardised questionnaires, tested for STIs at baseline and quarterly for 2 years. Risk compensation was defined as a significant increase (trend p<0.05) in the proportion of women reporting risky sexual behaviour or a diagnosed STI between baseline and end of follow-up. RESULTS: Between September 2013 and December 2016, 197 women (active arm: n=132 and placebo: n=65) were enrolled at the Masaka site. There were decreases in all markers of sexual risk behaviour with statistically significant decreases in only the proportion of women reporting ≥2 sexual partners, p=0.026 and those diagnosed with Trichomonas vaginalis p<0.001 and or Neisseria gonorrhoeae p<0.001 CONCLUSIONS: No evidence of risk compensation was observed in this trial. TRIAL REGISTRATION NUMBER: NCT01539226.