Mumps Outbreak in Shivamogga, India (2023–2024): Age-Specific Attack Rates, Complications, and an Economic Case for Measles-Mumps-Rubella Vaccine Inclusion in the Universal Immunization Programme

Background Recurrent mumps outbreaks continue to be reported in India, where the vaccine is not part of the national immunization schedule. Robust, age‑specific burden data from outbreak settings remain limited. Methods We conducted a retrospective investigation of pediatric mumps during epidemiologic weeks (EW)49‑2023 to EW8‑2024 across Subbaiah Institute facilities in Shivamogga, Karnataka, India. Clinically suspected cases were line-listed; laboratory confirmation used anti-mumps IgM enzyme-linked immunosorbent assay (ELISA). We described demographics, complications, and length of stay (LOS) among IgM‑confirmed cases, estimated age‑specific attack rates using district population denominators, and compared complication risks by age with exact tests and risk ratios (RRs; 95% CI). Vaccination status was ascertained from immunization cards/registers where available, otherwise by parental recall. Results Among approximately 2,500 clinically suspected cases during EW49-2023 to EW8-2024, 318 children (median age 6.5 years (IQR five to nine years); 49% female) were IgM-confirmed. The overall attack rate among children aged one to 16 years was 69 per 100,000 (95% CI 61.6-77.0), highest in the five-to-nine-year-old group (147 per 100,000) compared with