Overview of perinatal HIV infection

The global HIV epidemic is having a profound impact on the health and survival of children. As of 1994, it is estimated that about 2 million children worldwide (WHO, 1994) and 12 thousand children in the United States are HIV infected (Davis et al, 1995). Almost all HIV infection among infants and young children are from mother-to-infant transmission. By the year 2000, HIV is projected to infect 40 million men, women, and children unless effective prevention strategies are developed. Perinatal HIV transmission rates currently vary from 14-40% with the lowest rates being seen in Europe and highest rates in Africa. Known risk factors for perinatal transmission include advanced maternal HIV disease, lower CD4+ counts, and increased viral burden during pregnancy. Observational cohort data suggest that prenatal vitamin A levels, maternal drug use, and duration of membrane rupture during labor also are related to risk of transmission. The United States clinical trial utilizing an antiretroviral (zidovudine [AZT]) prenatally, intrapartum, and for 6 weeks to the infant demonstrated that perinatal HIV transmission was reduced by two-thirds. This dramatic result gives strong encouragement that simpler perinatal prevention strategies applicable to developing countries may also be successful. A number of international studies are underway or planned including perinatal vitamin A and micronutrient trials in Africa.