Prevention of mother-to-child transmission of HIV infection

PURPOSE OF REVIEW: Mother-to-child transmission of HIV infection is the primary cause of paediatric HIV infections worldwide. Although clinical trials show that antiretroviral therapy, elective caesarean section and formula feeding can significantly reduce the peripartum or postpartum risk of transmission, their application on a population basis is challenging. There is a need for alternative, easier and more effective interventions for population-based programmes. RECENT FINDINGS: This review addresses recent advances in our understanding of mother-to-child transmission risk factors, including maternal viral load (in plasma, genital tract and breast milk) and gender, and determinants and rates of postnatal transmission. New information on prophylactic antiretroviral therapy includes results from randomized trials in Africa and Thailand, in addition to new information on implementation of prevention of mother-to-child transmission programmes in nontrial settings, in both developed and developing countries. Two important issues relating to use of antiretroviral prophylaxis are discussed: safety and toxicity, including new findings on haemopoiesis, prematurity and mitochondrial abnormalities in antiretroviral therapy-exposed infants and children, and resistance. Recent trends and controversies relating to mode of delivery in HIV-infected pregnant women are outlined. Regarding infant feeding, preliminary results on use of mono-antiretroviral therapy to prevent postnatal transmission in breastfeeding HIV-exposed infants are discussed. SUMMARY: In resource-rich settings, virtual elimination of mother-to-child transmission is theoretically possible. Even in these settings, however, a substantial number of infected women are not being identified early enough for optimum application of prevention of mother-to-child transmission interventions. In developing country settings, focus is being directed towards scaling-up prevention programmes now that trials have established a variety of effective antiretroviral prophylactic approaches.