We thus propose to conduct a study comparing the standard-titre SW measles vaccine and the standard-titre EZ measles vaccine in a one- or two-dose schedule providing the first dose at 9 months of age, and then randomising the children at 18 months of age to receive either an additional dose of vaccine or nothing. The groups will be compared in terms of seroconversion-rate, proportion with an non-protective antibody level, geometric mean titer antibody level, vaccine efficacy, and child mortality. Further we plan to test the standard-titre EZ vaccine in a very early two-dose schedule providing the first dose at 4½ months of age and the second dose at 9 months of age (see also non-specific effect of vaccination).