Abstract
The efficacy of infant peri-exposure prophylaxis (PreP) to prevent HIV-1 postnatal transmission has never been assessed for the entirerecommended period of breastfeeding (12 months).The ANRS 12174 study is a randomised controlled trial comparing the efficacy and safety of lopinavir/ritonavir versus lamivudine to preventHIV-1 postnatal transmission in breastfeeding children born to HIV-1-infected mothers not eligible for ART (CD4 count above 350cells/mL) during breastfeeding (maximum 50 weeks). HIV-uninfected children aged 7 days were randomised for either drug in a 1:1 ratio.Infant HIV-infection status was assessed at week 6, 14, 26, 38 and 50 using HIV-1 DNA PCR. The study has completed enrolment in April2012 in Burkina Faso, Uganda, Zambia and South Africa. We report the current postnatal HIV-1 transmission rate and HIV-1 free survivalin the cohort among children aged 50 weeks or more in July 2012.By the end of July 2012, of 1273 children enrolled in the trial, 788 were aged 50 weeks or older. During this period, 8 transmissions occurredrepresenting a cumulative transmission rate of 1.1% (95%CI: 0.6-2.2). Interestingly, 6/8 transmissions occurred after 6 months ofbreastfeeding. Overall, 188 severe adverse events (grade 3 or more, DAIDS classification) and 22 deaths were identified. None were consideredattributable to the study drugs. The overall cumulative mortality was 3.0% (95%CI: 2.0-4.5) and HIV-1-free survival was 96.0%(95%CI: 94.3-97.2).Infant PreP is an efficacious strategy that could contribute to the elimination of HIV-1 transmission by breastfeeding.