Trend of measles, mumps, and rubella incidence following the measles-rubella catch up vaccination in the Republic of Korea, 2001.

Following the introduction of measles-rubella (MR) catch-up vaccination in 2001 and two dose measles-mumps-rubella (MMR2) keep-up program in 2002, the incidence of measles, mumps, and rubella was not evaluated systematically. To describe the recent changes in epidemiology, a population-based incidence study from 2001 to 2015 using national notifiable disease surveillance data was conducted. Between 2001 and 2015, there was decrease in the incidence of measles and rubella, whereas a steady increase in mump incidence was noted. The age distribution of mumps cases has shifted to the older age group, whereas rubella became more frequent in younger age group. The incidence of mumps showed an increase in every birth cohorts, except for the decrease in incidence for catch-up vaccination cohort from 131 cases in 2007-2011 to 64 cases per 100 000 in 2012-2015. Continuing in monitoring of mumps and strengthening of the high two-dose MMR vaccination coverage should be taken place in Korea.