Two transmissions occurred during breastfeeding, for a transmission rate of less than 1%; this rate is similar to or lower than those recently reported in smaller trials or observational studies in Africa.25-30 Although more transmissions occurred in the NRTI group than in the protease-inhibitor group or the observational group, the absolute numbers were low, and the difference was not significant. The two breastfeeding transmissions in the NRTI group were not associated with detectable HIV-1 RNA in either maternal plasma or breast milk.