First Mumps Outbreak in a Decade: Measuring Impact of Mumps Among Naïve Population—Tokunoshima Island Japan

摘要

BackgroundCurrently, mumps vaccine is not included in the routine vaccination program in Japan and consequently, nationwide mumps outbreak is observed approximately every 4 years. Tokunoshima Island, located in the southern part of Japan with population of 25,000, experienced island-wide mumps outbreak since July 2015. This outbreak was unique because unlike the rest of the country, the Island was not hit by mumps virus for last 10 years. Island being in an inconvenient location, and with less than 2% mumps vaccine coverage rate among one year old children every year, we considered that the population, especially less than 10 years old, is basically naïve to mumps virus. We conducted a comprehensive outbreak investigation to analyze the disease burden of mumps among mumps naïve Island population.