Neutralization activity and persistence of antibodies induced in response to vaccination with a novel mumps strain, RIT 4385

Background: We have previously shown that a new measles, mumps, rubella (MMR) vaccine, Priorix (TM), with a novel mumps component elicits anti-mumps antibody titers comparable to the licensed M-M-R (TM) II vaccine. Materials and Methods: To ensure that these antibodies had neutralizing activity against wild-type mumps virus, sera were prepared 2 and 18 months after vaccination of 12-24month-old infants with either Priorix (TM) or M-M-R (TM) II and ELISA antibody titers and neutralizing activity were determined. Results: After 2 months, Priorix (TM) and M-M-R (TM) II vaccines elicited comparable ELISA antibody titers and neutralizing activity, At 18 months ELISA seropositivity rates were 80-81% and 94-96% of vaccinees had neutralizing activity. ALL ELISA seropositives had neutralizing activity. Conclusion: These data suggest that both vaccines provided equivalent protection against mumps over this 18-month period.