Abstract Body

Background:

HIV transmission through breastfeeding remains a bottleneck to eliminate pediatric HIV infections in Africa. We aimed to assess the efficacy of a combined intervention including maternal viral load (VL) point of care (POC) testing and extended infant postnatal prophylaxis (PNP) to prevent postnatal transmission at 12 months in Lusaka (Zambia), Ouagadougou and Bobo-Dioulasso (Burkina Faso).

Methods:

Breastfed HIV-exposed infants were enrolled at the 2nd infant immunization visit (EPI-2, 6-8 weeks). A POC HIV DNA was done at EPI-2, and HIV-infected infants were promptly initiated on ART. HIV-exposed uninfected infants (HEU) infants and their mothers were then randomized to two arms. In the intervention arm, mothers had a POC VL testing during EPI-2 and M6 visits. Infants whose mothers had a VL >1000 cp/mL were initiated on lamivudine (3TC) until M12 or until 8 weeks after cessation of breastfeeding. The control group implemented PMTCT activities as per local WHO-derived guidelines. The primary outcome was infant HIV transmission at M12. Secondary outcomes were safety and the period at high risk of transmission defined as no PNP and a maternal VL >1000 cp/mL while breastfeeding.

Results:

From Dec 2019 to Sep 2021, 1526 HIV-exposed infants were enrolled and had HIV diagnosis at EPI-2. Among them, 20 infants were newly diagnosed with HIV, started prompt ART, and 1506 HEU infants (1342 from Zambia and 164 from Burkina Faso) were randomized (753 in each arm). Baseline characteristics were similar between arms. The mothers had a median age of 30.6 years (IQR:26.0-35.0), and 98.4% were on ART. In the intervention arm, the POC VL prompted 3TC initiation for 102 infants (85 at EPI-2 and 17 at M6). The period at high risk for transmission was 0.47/100 person-days (95%CI: 0.44-0.50) in the intervention arm vs. 6.58/100 person-days (95%CI: 6.47-6.70) in the control arm. Within 12 months of follow-up, 1 HIV transmission occurred in the intervention arm vs. 6 in the control arm, yielding transmission rates of 0.19/100 person-years (95%CI:0.005-1.05) and 1.17/100person-years (95%CI:0.43-2.55), respectively. The rate of SAE was similar in both arms.

Conclusions:

Our randomized controlled trial showed that an intervention nested in EPI and combining POC measurement of maternal viral load and, when unsuppressed, same-day infant single PNP initiation was safe and reduced the period at high risk of more than 90%, which resulted in a sharp reduction (though not significant) of HIV transmission at 12 months.