Effects of a Public Subsidy Program for Mumps Vaccine on Reducing the Disease Burden in Nagoya City, Japan

Nagoya City initiated a public subsidy program for mumps vaccination using either the Torii or Hoshino strains in August 2010. To determine the effects of the program, we used publicly available information from Nagoya City to investigate the changes in immunization rates and numbers of patients who developed post-immunization adverse reactions, including post-vaccinal aseptic meningitis, in the 7 years since its initiation. We also investigated the numbers of mumps patients reported by sentinel sites in a national database during this period. The immunization rate in one-year-old children increased from 24.3% before the program to 91.0% after 7 years. The mean numbers of reported mumps cases per sentinel site in one-year-old to preschool children the age groups targeted by the program were 12.9 in the 7 years before the program and 4.93 in the 7 years after initiation of the program, showing a significant decrease of 1/2.6 (p = 0.01). The number of vaccinations during the 6.5-year period was 140,316, with only one case of aseptic meningitis reported (0.7 cases/100,000 vaccinations). No other serious adverse reactions were observed. The present findings demonstrate that the public subsidy program in Nagoya City is an effective and safe measure against mumps in children.