In the proposed studies, the effect on mortality and morbidity of giving vitamin A supplementation simultaneously with BCG vaccination at birth to both normal and low birth weight infants will be investigated in an African population. Furthermore, the effects of vitamin A supplementation will be evaluated with respect to effect on growth, the response to BCG vaccination, infant vitamin A status and infant cytokine profile, malaria, measles, rotavirus infection and RSV infection. The mechanisms behind the effects of vitamin A will be evaluated. The potential interactions between vitamin A, sex and vaccines will be taken into account in all analyses.