Immune response to simultaneous administration of a combined measles, mumps and rubella vaccine with booster doses of diphtheria-tetanus and poliovirus vaccine.

A combined vaccine against measles (Edmonston-Zagreb 19 strain), mumps (Rubini strain) and rubella (Wistar RA 27/3 strain) was administered to a group of 46 children aged 10-12 months simultaneously with booster doses of compulsory diphtheria-tetanus toxoid and oral poliovirus vaccine. A second group of 53 children aged 15-24 months who had received booster doses of the compulsory vaccines 5 to 12 months before was also vaccinated. The same seroconversion rates (100%) and similar antibody titers for rubella were observed in both groups. The same seroconversion rates for mumps (93%) and similar rates for measles (98 and 94%) were observed in the two groups. Significantly lower antibody titers for measles and mumps were found in the first group, but they were compensated by an earlier protection, a reduction of number of visits for immunization, costs for the community, and improvement in parental compliance. These results confirm that Edmonston-Zagreb 19 and Rubini strains are still immunogenic even when they are combined with Wistar RA 27/3 strain. Moreover, a long term follow-up in order to verify the persistence of protective antibody levels in both groups of children, could suggest that combined measles, mumps and rubella vaccine could be given earlier (at 10-12 months of age), simultaneously with booster doses of diphtheria and tetanus toxoid and of trivalent oral poliovirus vaccine.