Background
Sexually transmitted infections (STIs) can signal ongoing risk of HIV acquisition and have adverse reproductive health sequalae. We assessed STI disease burden among women participating in the HPTN 084 trial during the blinded and unblinded period.
Methods
HIV uninfected women ages 18-45 years (y) in the HPTN 084 study were tested and treated for syphilis, Chlamydia trachomatis (CT), Neisseria gonorrhoea (NG) and Trichomonas vaginalis (TV) at baseline and every 6 months. We assessed baseline STI prevalence, post-baseline STI incidence rates; STI recurrence (≥2 episodes of CT, NG or TV >5 months apart), and concurrent STIs (≥2 STIs diagnosed within 7 days). Correlates of incident STIs were estimated using multiple regression. Cabotegravir (CAB) PrEP efficacy in the blinded study period was compared for people with and without STIs using Cox regression.
Results
Of 3224 women enrolled (median age 25y), 30.1% (95% CI 28.6%, 31.7%) had an STI at baseline. Among 2983(92.5%) women with follow-up data, 3111 incident STIs occurred over 7124 person years (PY), incidence rate (IR) 43.7 events/100PY [95% CI 42.2, 45.2]); most commonly CT (Table 1). STI IRs ranged from 18.5/100PY in Kenya to 49.4/100PY in Eswatini. Concurrent STIs were observed among 6.1% (95% CI 5.30%, 7.06%) of women at baseline and 14.4% (95% CI 13.1%, 15.7%) during follow-up; CT and NG were the most common concurrent infections. Of the 2983 women with follow-up data, 841(27.3%) had STI recurrence.
In multivariable analyses, STIs incidence was significantly higher among women18-24y vs women ≥25y (Relative Risk [RR] 1.52, 95% CI 1.40, 1.66); among single women (RR 1.79 95% CI 1.55, 2.08), women not living with partners (RR 1.66 95% CI 1.44, 1.92) vs women married/living as married; and women with no/primary education (RR 1.47 95% CI 1.22, 1.78) and secondary education (RR 1.22 95% CI 1.05, 1.42) vs those with higher education. There was no difference in CAB efficacy between women who had STIs (hazard ratio, HR, 0.08 95% CI 0.02-0.34) vs those who did not (HR 0.15 95% CI 0.03-0.64, p=0.58).
Conclusions
Curable STI prevalence, incidence and recurrence was high in this cohort of women accessing PrEP, highlighting the urgent need to prioritize investments in novel, multipurpose, and scalable interventions to prevent STIs and HIV among these women and their partners.