Background: The United Kingdom (UK) underwent a massive epidemic of mumps from 2003 through 2006. The origin and spread was mapped in 350 general practices that used office computers to contribute comprehensive medical information on approximately 3 million patients to the General Practice Research Database (GPRD).
Methods: The continuous 3-month cumulative incidence of mumps (2003-2006) was estimated by dividing the number of diagnosed cases of mumps each 3 months by the population at risk according to age, region, practice, and calendar time. The effect of the measles, mumps, and rubella (MMR) vaccine was estimated by comparing vaccine exposure of those diagnosed with mumps and those who were not.
Results: There were 5683 cases of mumps recorded in the Database over the 4-year time period. As the Database represents about 5% of the UK population, we estimate that there were more than 100,000 cases of mumps diagnosed in the UK during these 4 years. The epidemic appears to have started in one practice in Wales in the first 6 months of 2003 and then spread slowly north and east, reaching a peak in 2005. Young adults aged 18-24 years were at the highest risk. There were 3 major MMR vaccination campaigns (1988-1989, 1997, and 2004-2005) that by 2006 provided more than 70% protection against mumps in children younger than 18 years of age. Protection was higher in those who had received 2 doses of the vaccine.
Conclusion: A comprehensive program of medical information generated by selected general practitioners has provided a sound basis for the real-time recording of the origin, spread, and scope of an infectious disease.