Epidemiological study of mumps deafness in Japan.

In Japan, mumps vaccination is optional and the mumps were increased accompanied with prevalent waves according to the Infections Agents Surveillance Report (IASR). The aim of this study was to clarify that there was relevance for increase of mumps epidemic and mumps deafness. The Acute Profound Deafness Research Committee of the Japanese Ministry of Health and Welfare (reorganized to the Ministry of Health, Labour and Welfare in 2001) conducted a nationwide epidemiological survey to determine the number of patients treated for mumps deafness in 1987, 1993 and 2001. Based on its findings, the annual numbers of mumps deafness cases was estimated to be 300 in 1987, 400 in 1993 and 650 in 2001, which correlated with the overall incidence of mumps in those years. Because the majority of cases exhibited severe or profound sensorineural hearing loss that usually did not recover, rapid improvement of mumps vaccine coverage is strongly recommended.