Age-specific incidence of aseptic meningitis following mumps vaccination from 2013–2016: estimation based on the number of reported adverse reactions to immunization in Japan

抄録

First-dose mumps vaccination at a younger age may be associated with a lower risk of vaccine-associated aseptic meningitis. However, to date, there are no estimates of the age-specific incidence of aseptic meningitis caused by the Torii strain-derived mumps vaccine. We investigated post-vaccination aseptic meningitis incidence in Japan using case data from the Ministry of Health, Labour and Welfare regarding adverse reactions following the Torii strain-derived mumps vaccine. The number of age-specific vaccine administrations was estimated from an Internet survey dataset and the number of vaccine shipments. Using these numbers, we estimated the age-specific post-vaccination aseptic meningitis incidence. Between April 1, 2013, and April 30, 2016, the incidence among first-dose vaccinations was 3.5 cases and the incidence among 1-year-old recipients was 1.3 cases (per 100,000 doses). Compared with the incidence at 1 year, significantly higher rates were observed at ages 2–6, 7–12, and ≥13 years. Our results suggest that vaccination with the Torii strain-derived mumps vaccine at age 1 carries a lower risk of aseptic meningitis compared with administration of this vaccine at older ages.