SAFETY AND IMMUNOGENICITY OF CONCURRENT ADMINISTRATION OF MEASLES-MUMPS-RUBELLA-VARICELLA VACCINE AND PEDVAXHIB(R) VACCINES IN HEALTHY-CHILDREN 12 TO 18 MONTHS OLD

Objective. To determine the safety and immunogenicity of concurrent ad ministration of measles-mumps-rubella-varicella vaccine (MMRV) and Ped vaxHIB(R) (Haemophilus influenzae type b conjugate vaccine) vs. M-M-R( R)(II) and PedvaxHIB(R) followed by an optional dose of VARIVAX(R) 6 w eeks later. Design. Healthy children, 12 to 18 months of age, were ran domly assigned to two groups to receive (1) MMRV and PedvaxHIB(R) give n concurrently or (2) M-M-R(R)(II) and PedvaxHIB(R) followed by an opt ional dose of VARIVAX(R) 6 weeks later. Subjects. The study group incl uded 294 healthy children, ages 12 to 18 months, with a negative histo ry of measles, mumps, rubella and varicella. Main outcome measures. Th e seroconversion rate and magnitude of antibody responses when MMRV wa s giver, concurrently with PedvaxHIB(R) compared with the antibody res ponses when VARIVAX(R) was given 6 weeks after M-M-R(R)(II) and Pedvax HIB(R). Results. Healthy children, 12 to 18 months of age, who receive d MMRV and PedvaxHIB(R) concurrently showed immune responses similar t o those in the control group who received M-M-R(R)(II) vaccine with Pe dvaxHIB(R) followed by VARIVAX(R) 6 weeks later. Antibody titers for v aricella wore significantly lower when MMRV was administered than when varicella vaccine was given separately (0.712-fold difference, P = 0. 028). No vaccine-related serious adverse reactions were reported, and no clinically significant differences were seen in the safety profiles of the two treatment groups. Conclusions. There were no statistically significant differences in the seroconversion rates between the two t reatment groups for any of the antigens tested at 6 weeks and 1 year. Significantly lower geometric mean titers for varicella were noted in the group who received MMRV compared to VARIVAX(R) given alone. Six-we ek seroconversion rates, persistence of immune responses at 1 year and the frequency of local and systemic reactions were comparable when MM RV was administered with PedvaxHIB(R) compared with M-M-R(R)(II) and P edvaxHIB(R) followed by VARIVAX(R) 6 weeks later.