Mother-to-child transmission of HIV

Abstract

The first children with HIV-1 infection were described in 1983. As of 1998, the global HIV epidemic is having a profound impact on the health and survival of children. Almost all HIV infections among young children are due to vertical transmission, and the intrapartum period appears to provide us with a crucial window of opportunity for prevention. Postnatal transmission through breastfeeding also contributes an estimated one third to one half of vertical transmission worldwide. Carefully conducted epidemiologic studies are elucidating the immunologic, virologic, and behavioral factors affecting the risk of HIV-1 transmission from mother to infant and the natural history of HIV disease in perinatally infected children. Transmission of HIV-1 is influenced by many factors, and a high maternal viral load is insufficient to fully explain vertical transmission of HIV-1. Pediatricians and other providers should counsel HIV-infected women about the means available to decrease the risk of HIV transmission to the infant. However, the majority of HIV-infected children are born in the developing world, and a crucial challenge is to identify safe and effective interventions that are feasible in those countries with the most significant HIV burden.

PIP: Pediatric infection has emerged as an important public health problem in both industrialized and developing nations. An estimated 15,000 HIV-infected children were born to HIV-positive women in the US through 1993. The risk of transmission from an infected mother to her infant ranges from about 15% to 45%, with the highest rate reported in sub-Saharan Africa. Almost all HIV infections among young children are due to vertical transmission and the intrapartum period appears to provide a crucial window of opportunity for prevention. Postnatal transmission through breast-feeding also contributes an estimated one-third to one-half of vertical transmission cases worldwide. This paper also presents some epidemiologic studies delineating the immunologic, virulogic, and behavioral factors affecting the risk of HIV-1 transmission from mother to infant and the natural history of HIV disease in perinatally infected children. HIV-1 transmission is influenced by several factors. Known correlates of mother-to-child transmission include high maternal plasma viremia, advanced clinical HIV disease, reduced maternal immunocompetence, prolonged time interval between rupture of amniotic membranes and delivery, and direct exposure of the fetus to maternal blood during the delivery process. However, a high maternal viral load is insufficient to fully explain its vertical transmission. This paper suggests that health providers should counsel HIV-infected women about the available means to decrease the risk of HIV transmission to the infant.