The Defense Medical Surveillance System is a database containing up-to-date and historical data on disease and medical events as well as longitudinal data on personnel and deployments. The system provides the data supporting the Department of Defense Serum Repository which as of Spring 2010 includes over 50 million serum specimens drawn from servicemembers (since the late 1980s) and used to perform longitudinal analyses of service member health. The system also also supports the Defense Medical Epidemiology Database.