Rousseau CM, Nduati RW, Richardson BA, et al. J Infect Dis. 2003;187:741–747
Purpose of the Study.
Transmission of human immunodeficiency virus (HIV) via breastfeeding may occur throughout lactation. In developing countries, where >90% of HIV-exposed children live, safe alternatives to breastfeeding are not available. An understanding of the dynamics of breast milk virus levels and the correlation of breast milk virus levels with mother-to-child transmission is essential for the development of effective interventions.
A total of 648 breast milk samples were collected from 275 women enrolled in a clinical trial in Nairobi, Kenya, between 1992 and 1998. Antiretroviral regimens were not available to the women at the time of the study. Breast milk samples were analyzed for virus levels, and infants were monitored for up to 2 years, for assessment of HIV transmission.
The average duration of breastfeeding was 21 months. Of the 275 women, 70 transmitted HIV to their infants and 205 did not. Greater maternal plasma viral loads, lower maternal CD4+ T cell counts, and detection of HIV DNA in maternal genital secretions were significantly associated with elevated breast milk HIV RNA levels. The median viral load in early milk was significantly greater than that in breast milk collected 14 days after delivery. Breastfeeding mothers who transmitted HIV had significantly higher breast milk HIV RNA levels and more consistent viral shedding, compared with mothers who did not transmit HIV.
The risk of infant infection through breastfeeding was increased by higher levels of virus in breast milk; levels were highest early after delivery.
In developing countries, the rate of perinatal HIV transmission approaches 50%. This is dramatically higher than the 20% to 25% rate of transmission that was noted in developed countries before the initiation of perinatal antiretroviral therapy. It is now clear that breastfeeding is a significant factor in the transmission of HIV from mother to child and may be responsible for ≥30% of transmissions in developing countries. Unfortunately, safe alternatives to breastfeeding do not exist for most HIV-positive women. Provision of effective perinatal antiretroviral therapy, combined with safe alternative feeding methods, is required to significantly affect the extraordinary rate of HIV disease among children in the developing world.