Abstract
Background Concerns regarding risk compensation following initiation of oral HIV pre-exposure prophylaxis (PrEP) remain an important consideration in HIV prevention programmes. However, evidence on behavioural changes following PrEP initiation within pharmacy-delivered models particularly among adolescents and young adults. in sub-Saharan Africa remains limited. This study evaluated short-term changes in sexual risk behaviours among young adults receiving pharmacy-delivered oral PrEP in Nigeria. Methods We conducted a prospective implementation study among young adults aged 18–24 years initiating oral PrEP through two community pharmacies in Abuja, Nigeria. Participants completed behavioural assessments at baseline and one month following PrEP initiation. Risk compensation behaviours assessed included condomless sex, transactional sex, sex under the influence of alcohol or drugs, sexually transmitted infection (STI) diagnosis, and number of sexual partners. Paired behaviour changes between baseline and Month 1 were assessed using McNemar’s test for categorical variables and Wilcoxon signed-rank test for continuous variables. Firth penalized logistic regression guided by the Health Belief Model evaluated predictors of increased sexual risk behaviours following PrEP initiation. Results Among 197 participants initiating PrEP, 90 completed paired behavioural assessments at Month 1. Median age was 24 years (IQR: 22–24), 71% were female, and 93% were single. No significant increase in sexual risk behaviours was observed following PrEP initiation. Condomless sex remained stable between baseline and Month 1 (21.2% vs 19.0%; p = 1.000), while transactional sex (41.1% vs 32.2%; p = 0.080) and sex under the influence of alcohol or drugs (51.1% vs 42.2%; p = 0.170) did not significantly increase. STI diagnosis significantly decreased from 37.8% at baseline to 11.1% at Month 1 (p < 0.001), and the distribution of partner numbers shifted downwards significantly from baseline to Month 1 (median 2 [IQR: 1–4.75] vs 2 [IQR: 1–3]; p = 0.011). In Health Belief Model-based regression analyses, High perceived HIV risk was significantly associated with lower odds of increased transactional sex following PrEP initiation (OR = 0.13; 95% CI: 0.01–0.85; p = 0.034). Conclusion This study found no evidence of substantial short-term risk compensation following initiation of pharmacy-delivered oral PrEP among young adults in Nigeria. Sexual risk behaviours remained stable or decreased after PrEP initiation, suggesting that pharmacy-delivered PrEP can be implemented without significant behavioural risk escalation in this population. Larger longitudinal studies are needed to evaluate longer-term behavioural outcomes.