Measles among under-9-month-olds in rural Bangladesh: its significance for age at immunization.

Any decision to modify measles immunization strategies away from the use of the conventional vaccine given to children at 9 months of age to the adoption of recently proposed vaccine strains that can be given to 4-6-month-olds will depend on the age distribution of severe cases of measles in the community. Reported are the results of an analysis of two community-based measles surveillance systems in rural Bangladesh, which found that 17% of all measles cases reported for under-5-year-olds in a nonvaccinated population involved infants aged less than 9 months. In a vaccinated population from the same area, 31% of all measles cases reported for under-5-year-olds occurred among under-9-month-olds. Using a rather restrictive definition for measles-related deaths (those occurring within 6 weeks of the onset of the rash), the proportion of measles-related deaths that occurred before 9 months of age was 13% of all such deaths that were reported.