[Cost-effectiveness analysis of routine mumps immunization in Japan]

Mumps immunization is not included in routine immunization in Japan. We measured the cost-effectiveness of routine immunization.

We surveyed outpatients prospectively from June 15, 2004, for 19 months in an area with a population of 100,000. Almost all of the 11 pediatric clinics and hospitals in this area cooperated. In 2006, we retrospectively surveyed all inpatients hospitalized for more than 24 hours and dying of mumps.

We collected data from 189 doctors who rated outpatients and 112 families. The disease burden for outpatients including family nursing was estimated to be 47.1 billion yen nationwide. We estimated the total number of inpatients as 4,596. The disease burden of inpatients including the cost of family nursing was estimated to be 1.35 billion yen. Adding cases of sequelae and death, the total disease burden was estimated to be 52.5 billion yen. The incremental benefit cost ratio for routine immunization is higher than 1 even in the lower bounds of the 95% confidence interval.

The incremental benefit cost ratio shows that the additional benefit due to routine immunization exceeds additional cost, emphasizing the benefits of routine mumps immunization.