Mother-to-child transmission of HIV-1

More than 90% of HIV-1 infection in children is acquired by mother-to-child transmission. A recent evaluation in Europe estimated that one out of seven children born to HIV-1-infected women was infected, but transmission in Africa seems to be considerably higher. Factors influencing the risk of transmission include load and replicative properties of the virus as well as the neutralizing antibody response of the mother. A recently concluded trial with zidovudine administered to pregnant women and their newborn infants achieved a two-third reduction in the transmission rate. This knowledge together with a better understanding of timing of transmission is of extreme importance for further planning of focused interventional approaches to reduce transmission.