A phase II clinical trial conducted in Burkina Faso suggests that targeted lamivudine prophylaxis in infants born to mothers with HIV and high viral loads can significantly reduce the risk of HIV acquisition. The PREVENIR-PEV trial, a non-randomized study, implemented an optimized strategy triggered at the 2nd immunization visit (EPI-2) to prevent HIV acquisition by infants. The findings offer a promising approach to further reduce mother-to-child transmission (MTCT) rates in resource-limited settings.
The study enrolled mother-infant pairs between December 2019 and December 2020. Infants born to mothers with a viral load (VL) ≥ 1000 copies/mL at the EPI-2 visit received generic lamivudine oral solution until 12 months of age or 1-2 months after breastfeeding cessation. The primary outcome was the rate of new infant HIV-1 infection between 8 weeks and 12 months of age.
The trial was conducted in Bobo-Dioulasso, Burkina Faso, where the estimated HIV prevalence in women aged 15–49 was 0.7% and the MTCT rate was 14.7% in 2022. The national prevention program at the time consisted of nevirapine administered to newborns of HIV-infected mothers for 6 weeks.
Key Findings
The primary outcome, the rate of new infant HIV-1 infection between 8 weeks (EPI-2) and 12 months of age, was a key measure of the intervention's success. Secondary outcomes included the proportion of infants diagnosed with HIV for the first time at EPI-2 and the rate of serious adverse events among HIV-exposed uninfected (HEU) infants receiving lamivudine prophylaxis between the EPI-2 and 12-month visits.
Infants with negative HIV test results continued follow-up in the PREVENIR-PEV trial. Mothers completed questionnaires on sociodemographic data, medical history, prevention of mother-to-child transmission (PMTCT) received by the infant at birth, and maternal ART. Infants were clinically assessed, and maternal VL was quantified. HEU infants of mothers with a VL ≥ 1000 cp/mL were considered at high risk for HIV acquisition during breastfeeding. These infants received generic lamivudine oral solution (7.5 mg twice daily if the weight of the infant ranged from 2–4 kg, 25 mg twice daily if 4–8 kg, and 50 mg twice daily if > 8 kg) until 12 months of age or until 1–2 months after breastfeeding cessation.
Implications for MTCT Prevention
The results suggest that targeted lamivudine prophylaxis, guided by maternal viral load at the EPI-2 visit, can be an effective strategy to further reduce MTCT rates. This approach allows for optimized prevention efforts, focusing on infants at the highest risk of HIV acquisition during breastfeeding. The study highlights the importance of integrating viral load monitoring into existing immunization programs to identify and protect vulnerable infants.
