Background: A quadrivalent measles, mumps, rubella and varicella vaccine would facilitate universal immunization against all 4 diseases, improve compliance and immunization rates and decrease the number of injections given to children and visits to physicians' offices.
Objectives: To evaluate 1- and 2-dose regimens of a combined measles, mumps, rubella and varicella vaccine (ProQuad, referred to as MMRV) manufactured with a varicella component of increased potency.
Methods: In this partially blind, multicenter study, 480 healthy 12- to 23-month-old children were randomized to receive either MMRV and placebo or M-M-RII and VARIVAX. Injections were given concomitantly at separate sites. Subjects randomized to receive MMRV and placebo received a second dose of MMRV 90 days later. Subjects were followed for 42 days after each vaccination for adverse experiences. Immunogenicity was evaluated 6 weeks after each vaccination.
Results: Measles-like rash and fever during days 5-12 were more common after the first dose of MMRV (rash, 5.9%; fever, 27.7%) than after M-M-RII and VARIVAX (rash, 1.9%; fever, 18.7%). The incidence of other adverse events were similar between groups. Response rates were >90% to all vaccine components in both groups. Geometric mean titers to measles and mumps were significantly higher after 1 dose of MMRV than after administration of M-M-RII and VARIVAX. The second dose of MMRV elicited slight to moderate increases in measles, mumps and rubella antibody titers and a substantial increase in varicella antibody titer (from 13.0 to 588.1 glycoprotein antigen-based enzyme-linked immunosorbent assay units/mL).
Conclusion: A 1- or 2-dose regimen of MMRV is generally well-tolerated when administered to 12- to 23-month-old children and has a safety and immunogenicity profile similar to that of M-M-RII and VARIVAX administered concomitantly.