Antibody response to measles immunization in rural Ghanaian infants.

We investigated optimal age of measles immunization in infants aged 3-11 months in rural villages of Ghana, and determined seroconversion rate in the same infant population following further attenuated measles vaccination with Schwarz vaccine. The prevalence of passively acquired antibody was 11 per cent in infants younger than 6 months, 10 per cent in infants 6 months old, and 3 per cent in infants 7 months old or older. Seroconversion rates in each age group were less than 50, 87, and 92 per cent, respectively. We then immunized 47 7-month-old infants. The seroconversion rate was 92 per cent in this group. There were no clinical adverse effects due to the vaccination. We conclude that measles vaccination could be administered effectively at the age of 7 months with an excellent seroconversion rate.