Universal measles-mumps-rubella vaccination to new recruits and the incidence of mumps in the military

In response to the resurgence of mumps, the Korean Armed Forces started the measles-mumps-rubella (MMR) vaccination to all new recruits regardless of prior vaccination history. We evaluated the effectiveness of the vaccination by comparing the incidence between the military and civilian populations before and after implementation of the new policy. The standardized incidence ratio of mumps in the military was 7.06 in the prevaccine period, which declined to 0.96 in the postvaccine period. Vaccine effectiveness was estimated at 86.4%. Incidence rate ratio was lower in the 1996-1998 birth cohort (BC) compared with 1989-1995 BC (0.10 vs. 0.55), suggesting higher effectiveness of vaccination in the 1996-1998 BC. Our data provide evidence for the use of the MMR vaccination in the prevention of mumps in high-risk adults.