Objective. To determine the safety and immunogenicity of concurrent administration of measles-mumps-rubella-varicella vaccine (MMRV) and PedvaxHIB® (Haemophilus influenzae type b conjugate vaccine) vs. M-M-R®II and PedvaxHIB® followed by an optional dose of VARIVAX® 6 weeks later.
Design. Healthy children, 12 to 18 months of age, were randomly assigned to two groups to receive (1) MMRV and PedvaxHIB® given concurrently or (2) M-M-R®II and PedvaxHIB® followed by an optional dose of VARIVAX® 6 weeks later.
Subjects. The study group included 294 healthy children, ages 12 to 18 months, with a negative history of measles, mumps, rubella and varicella.
Main outcome measures. The seroconversion rate and magnitude of antibody responses when MMRV was given concurrently with PedvaxHIB® compared with the antibody responses when VARIVAX® was given 6 weeks after M-M-R®II and PedvaxHIB®.
Results. Healthy children, 12 to 18 months of age, who received MMRV and PedvaxHIB® concurrently showed immune responses similar to those in the control group who received M-M-R®II vaccine with PedvaxHIB® followed by VARIVAX® 6 weeks later. Antibody titers for varicella were 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 treatment 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® given alone. Six-week seroconversion rates, persistence of immune responses at 1 year and the frequency of local and systemic reactions were comparable when MMRV was administered with PedvaxHIB® compared with M-M-R®II and PedvaxHIB® followed by VARIVAX® 6 weeks later.