 While it is becoming clearer that young infants in developing countries with endemic vitamin A deficiency are at significant risk of being vitamin A deficient in spite of adequate breast feeding behaviour, there is little data concerning the impact of supplementing this group with vitamin A. Two major studies have addressed this issue, both done by the same group at Johns Hopkins University, with opposite findings. Humphrey et al. have reported, in a randomized clinical trial of 2067 infants born in a hospital in Bandung, Indonesia, that direct supplementation of newborn infants within 24 hours of birth with 50,000 IU of vitamin A was safe 10 and associated with a 64 reduction in infant mortality 11. In contrast, West et al. studied over 11,000 infants under six months of age in their large intervention trial in southern Nepal 17. They found no difference in mortality between those supplemented with vitamin A versus those given placebo relative risk 1.11, 95 CI 0.86 - 1.42. However, there were significant and potentially important differences between these two studies. First, the time of dosing was different. The Indonesian study dosed infants within 24 hours of birth whereas the Nepal study dosed infants when they were first identified to the study during their distribution rounds every four months. On average then, the age at first dosing was 2 months after the highest risk period and exposure to dietary and other environmental factors. It may be that the time of dosing is critically important for the development of early immune function or other protective mechanisms. Support for the Indonesian findings has come from a recently discussed study in Bangladesh where supplementation of mothers post-partum was associated with a reduction in infant mortality 12. 