Risk‐based versus universal PrEP delivery during pregnancy: a cluster randomized trial in Western Kenya from 2018 to 2019

INTRODUCTION: Integrating pre‐exposure prophylaxis (PrEP) delivery for pregnant and postpartum women within maternal and child health (MCH) clinics is feasible and acceptable. It is unknown whether a risk‐guided model would facilitate appropriate PrEP use among MCH attendees better than universally offering PrEP. METHODS: The PrEP Implementation for Mothers in Antenatal Care (PrIMA) study was a cluster randomized trial to assess two models for PrEP delivery among pregnant women seeking routine MCH care at 20 public clinics in Kenya between January 2018 and July 2019 (NCT03070600). In the Universal arm, all participants received PrEP counselling and self‐selected whether to initiate PrEP. In the Targeted arm, participants underwent an HIV risk assessment, including an objective risk‐scoring tool and an offer of HIV self‐tests for at‐home partner testing; those determined to be at high risk received a PrEP offer. Participants were followed through 9 months postpartum. Primary outcomes included incident HIV and appropriate PrEP use (defined as PrEP uptake among those at high risk and no PrEP uptake for those not at risk). Outcomes were compared using intention‐to‐treat analyses, adjusting for baseline HIV risk and marital status. RESULTS: Among 4447 women enrolled, the median age was 24.0 years (interquartile range [IQR]: 20.9, 28.3), and most were married (84.8%). The median gestational age at enrolment was 24 weeks (IQR: 20, 30). Women in the Targeted arm were more likely to be at high risk for HIV acquisition at baseline (51.6% vs. 33.3%). During 4638 person‐years (p‐yr) of follow‐up, there were 16 maternal HIV infections with no difference in maternal HIV incidence between arms: 0.31/100 p‐yr (95% CI: 0.15, 0.65) Targeted and 0.38/100p‐yr (95% CI: 0.20, 0.73) Universal (adjusted relative risk [aRR]: 0.85 [CI: 0.28, 2.55]). There was no significant difference in the frequency of appropriate PrEP use between the arms (68.2% vs. 59.1% in Targeted vs. Universal, respectively) (aRR: 1.03 [CI: 0.96, 1.10]). CONCLUSIONS: Given comparable maternal HIV incidence and PrEP uptake in Universal and Targeted approaches, and the simplicity that universal PrEP offers, our findings suggest that universal PrEP counselling is optimal for integrating PrEP in MCH systems.