Measles in Tanzania: antibody response in children after vaccination and antibody state of mothers and newborns.

The antibody response to attenuated live measles vaccines was studied in two groups of 29 (A) and 53 (B) African children. In group A 22 sera and in group B 34 sera showed no pre-immunization haemagglutination inhibition (HI) titres. Vaccination resulted in seroconversion in 64 and 85% of groups A and B, respectively. The difference in antibody response between the two groups could be traced to children in the age group seven to eight months, where seroconversion was absent in 67% of group A children and in 0% of group B children. Antibody levels were studied in 234 mothers and their newborns. In 131 serum pairs the antibody levels of mother and child were similar. 78 (33%) of mothers showed a higher titre and 25 (11%) a lower titre than their babies. All newborns except one and all mothers except one possessed antibody titres above 10. Children in the age groups seven to eight months and nine to ten months showed antibody in 12 and 7%, respectively. Over 90% of these children had not been infected in the first ten months of life.