A substantial proportion of children <12 months of age develop measles in both endemic and epidemic situations. Studies in African children indicate that the AIK-C measles vaccine is more immunogenic than Schwartz vaccine in children <12 mo., with persistent maternal antibody.

U.S. infants (368) were equally randomized to receive, at 6 months of age: 1) AIK-C vaccine (Pasteur Merieux, France, 3.9 log10 TCID50); 2) Moraten vaccine (Merck, ≥3 log10 TCID50); or placebo. Measles antibody titers were measured by hemagglutination inhibition (HI) and plaque neutralization (PN) on pre-vaccination and 2 month post-vaccination sera. Titers were converted to mIU/ml by use of WHO standard. Serum immune responses of the first 266 children follow: Table There were NS differences in seroresponses to the 2 vaccines at 6 months of age. Serum immune responses to MMR vaccination at 12 months and antibody persistence at 24 mo. will be measured.

Table 1

We conclude that 2 mo. post-immunization there is no apparent immunological advantage of using AIK-C, in place of Moraten, for 6 month old U.S. children. Funded by Pasteur Merieux Connaught.