Immunogenicity and safety of a varicella vaccine (Okavax) and a trivalent measles, mumps, and rubella vaccine (Trimovax) administered concomitantly in healthy Filipino children 12-24 months old

The immunogenicity and safety of Okavax trade mark varicella vaccine, when administered concomitantly with Trimovax trade mark measles, mumps, and rubella (MMR) vaccine, were assessed in 300 Filipino children 12-24 months old. Three groups received Okavax only, Trimovax only, or both vaccines concomitantly. In sera obtained six weeks after vaccination, high varicella antibody geometric mean titers (GMTs) (115 and 79.8 mIU/mL, respectively) and seroconversion rates (>or= 91.9%) were similar for Okavax given alone or concomitantly with Trimovax. High MMR GMTs and seroconversion rates (mumps >or= 94.6%, measles and rubella >or= 98.6%) were not affected by concomitant administration of Trimovax with Okavax. Solicited local and systemic reactions recorded by parents were slightly more numerous after concomitant administration, but the majority of all reactions were mild and transient. The good tolerance and high immunogenicity observed supports the concomitant administration of Okavax and Trimovax to children in their second year of life to protect against four life-threatening diseases while simplifying childhood immunization programs.