The impact of MMR vaccine on mumps infection in England and Wales.

In the absence of an immunisation programme, epidemics of mumps have occurred at three-yearly intervals in England and Wales. Mumps has been the commonest cause of viral meningitis in children. Routine immunisation (as part of combined measles/mumps/rubella vaccine) was introduced in 1988 and has had a substantial impact on the disease. There has been a 79% reduction in notified cases over two years and the epidemic cycle has been interrupted. Prospects for elimination are good.