Background: Few studies have investigated the effects of teacher training and continued support on teachers' delivery of evidence-based HIV prevention programs. We examined these factors in a national implementation study of an evidence-based HIV risk reduction intervention for adolescents in the sixth grade in the Bahamas.

Methods: Data were collected from 126 grade 6 teachers and 3,118 students in 58 government elementary schools in the Bahamas in 2019-2021. This is a Hybrid Type III implementation study guided by the Exploration, Preparation, Implementation, Sustainment (EPIS) model. Teachers attended 2-day training workshops. Trained school coordinators and peer mentors provided biweekly monitoring and mentorship. We used mixed-effects models to assess the effects of teacher training and continued support on implementation fidelity.

Results: Teachers who received training in-person or both in-person and online taught the most core activities (27.0 and 27.2 of 35), versus only online training (21.9) and no training (14.9) (F = 15.27, p < .001). Teachers with an "excellent" or "very good" school coordinator taught more core activities than those with a "satisfactory" coordinator or no coordinator (29.2 vs. 27.8 vs. 19.3 vs. 14.8, F = 29.20, p < .001). Teachers with a "very good" mentor taught more core activities and sessions than those with a "satisfactory" mentor or no mentor (30.4 vs. 25.0 vs. 23.1; F = 7.20; p < .01). Teacher training, implementation monitoring, peer mentoring, teachers' self-efficacy, and school-level support were associated with implementation fidelity, which in turn was associated with improved student outcomes (HIV/AIDS knowledge, preventive reproductive health skills, self-efficacy, and intention to use protection).

Conclusion: Teachers receiving in-person training and those having higher-rated school coordinator and mentor support taught a larger number of HIV prevention core activities. Effective teacher training, implementation monitoring, and peer mentoring are critical for improving implementation fidelity and student outcomes.