Prevention of mother-to-child transmission of HIV-1.

More than 90% of the estimated 4–8 million children who have HIV infection acquired HIV-1 from their mothers (www.unaids.org) [1]. In the next decade, 5–10 million children will be infected with HIV through mother-to-child transmission (MTCT) in the absence of interventions [1]. Available antiretroviral drugs are successful in diminishing mother-to-child transmission of HIV-1. In 1994 the results of a randomized clinical trial (PACTG 076) demonstrated that an antiretroviral drug, zidovudine, diminished transmission of HIV from mothers to their infants [2]. The magnitude of the effect was unexpected, with a 67% reduction occurring in infants born to treated mothers. This finding encouraged the development of US Public Health Service (USPHS) guidelines for counselling and testing of pregnant women, and for antiretroviral management of pregnant women [3,4]. Over the subsequent 5 years the number of infants reported with AIDS has decreased by 75% in the USA [5]. Similar decreases have occurred in other developed nations that have the resources to administer antiretroviral drugs to pregnant women. The rapidity of the nationwide decline in pediatric HIV infection in the USA, and the effectiveness of the regimen in routine antenatal care, which is comparable to the efficacy of the clinical trial, have been gratifying. This too was not predicted because problems of access, acceptance and adherence to the regimen could have diminished the effectiveness in the real world, which lacks the resources and monitoring afforded by a randomized clinical trial. We now understand how to prevent infection in the vast majority of exposed infants. In the USA an estimated 6000–8000 HIV-infected women deliver infants annually [6]. Before the use of antiretroviral drugs during pregnancy, an estimated 1800 infected infants were born each year. At the present time, in the developing world where more than 90% of HIV infections in children have occurred, an estimated 1600–1800 HIV infected infants are born daily [1]. There are more than 600000 infected infants born each year with an estimated 500000 annual deaths [1]. In the single nation of Botswana, with a population of approximately 1.4 million people, the HIV seroprevalence in women of childbearing age is approximately 40% nationwide [1]. This results in the birth of an estimated 7000–9000 HIV-infected infants annually, which is three to five times the number of infected infants born each year in the USA prior to 1994. This illustrates the magnitude of the crisis, which is shared by other sub-Saharan African countries. The ‘technology’ of the developed world has not been successfully implemented in most of the developing world for a number of reasons. In September 1999 Guay et al. [7] observed that nevirapine administered as a single dose to the mother and a single dose to the newborn diminished HIV transmission by 47% in a randomized clinical trial (HIVNET 012) in Uganda. This knowledge provides the world with the opportunity to protect at least half of infants born to HIV-infected women who would be infected in the peripartum period. It is an urgent imperative that the global community mobilize to appropriately implement this effective intervention to protect a future generation from acquiring HIV infection. Implementation requires resources, collaboration, and additional research.