Prevention of breast milk transmission of HIV: the time is now.

breastfeeding. 1 Although effective interventions are also available to reduce in utero and intrapartum transmission in resource-limited settings, postnatal transmission of HIV through breastfeeding has remained a significant problem. 2 Acquisition of HIV through breast milk accounts for an estimated 40% of new infections in sub-Saharan Africa, where more than 90% of perinatal infection occurs. 3,4 Replacement feeding from birth is not feasible or safe in many resource-limited countries due to cost, lack of a safe water supply, the stigma of being associated with HIV infection, and the high risk of mortality and morbidity from diarrhea, pneumonia, and malnutrition in infants who are not breastfed, which can outweigh the risks associated with HIV itself. 5‐7 HIV-infected mothers in these settings have faced a difficult if not impossible choice—to breastfeed but risk transmitting HIV to their infant or to not breastfeed and risk their infant dying of other infectious diseases or malnutrition. Exclusive breastfeeding has been shown to lower the risk of postnatal HIV transmission compared with mixed feeding, but does not to eliminate risk. 8,9 In the past year, exciting new results from observational studies and randomized clinical trials have become available that provide potential solutions to this difficult dilemma. In this issue of JAIDS, Kilewo et al 10 present results of the observational MitraPlus study. In this study, highly active combination antiretroviral therapy (HAART) was provided to HIV-infected pregnant women starting at 34 weeks gestation and continued through up to 6 months of breastfeeding. The cumulative risk of HIV infection was 5% at 6 months and 6% at 18 months of age; the risk of postnatal infection between 6 weeks and 6 months was only 1%. This risk is significantly lower than observed in breastfeeding infants in the Petra trial arm A, in which zidovudine (AZT)/lamivudine (3TC) was provided starting at 36 weeks gestation, intrapartum, and for 1-week postpartum, with no further postnatal prophylaxis 11 ; in this study, the risk of postnatal HIV infection between 6 weeks and 6 months was 6.5%, with cumulative transmission of 16.4% at 6 months and 17.7% at 18 months of age. Several other observational studies have also suggested that maternal HAART during breastfeeding reduces postnatal HIV transmission. 12‐14 An alternative intervention that has been evaluated to reduce postnatal infection is antiretroviral prophylaxis given to the infant. The Mitra study was an earlier observational study conducted by Kilewo et al in the same clinics in which they subsequently conducted Mitra-Plus. In Mitra, mothers were given AZT/3TC from 36 weeks gestation to 1-week postpartum, combined with 1-week AZT/3TC to the infant, followed by administration of daily 3TC to the infant during breastfeeding for a maximum of 6 months. 15 The cumulative infection rate was 3.8% at 6 weeks and 4.9% at 6 months of age, with the risk of postnatal HIV infection between 6 weeks and 6 months 1.1%, remarkably similar to what is reported in the current study with maternal HAART prophylaxis. Two randomized, controlled clinical trials were published last year that also demonstrated that infant prophylaxis with daily nevirapine (NVP) or NVP/AZT significantly