Mumps Antibody Titer in MMR-Vaccinated and Vaccine Naïve Children at a Public Hospital in Delhi.

To compare the mumps antibody titers in Measles-Mumps-Rubella (MMR)-vaccinated and vaccine naive children. This cross-sectional study was conducted at a tertiary-care public hospital in Delhi from November, 2016 to April, 2018 among 78 healthy children (aged 16 month-12 years) attending the pediatric outpatient department. Serum IgG and IgM rubella antibodies were measured by ELISA for confirmation of MMR vaccination status. Qualitative determination of IgG mumps was done followed by quantitative determination in samples positive for IgG mumps antibodies. IgG mumps was present in 69.2% of study population, with seroprotective titers in 32% taking endpoint titer as 1:4. Among MMR vaccinated children, 41.1% were sero-protected and in MMR vaccine naïve children 9.1% were seroprotected for mumps. Single dose of MMR vaccine does not provide effective (>90%) sero-conversion required for successful herd immunity to prevent mumps outbreak.