Abstract
We determined the utility and effective methodology for combining patient record information from the Departments of Veterans Affairs (VA) and Defense (DoD). The surveillance systems are complementary with evident benefits when merged. The VA system patient volume roughly doubles the DoD system, and provides better geographic coverage in lower population densities; however, the DoD includes younger populations, better coverage in strategic metro areas, and more pre-diagnostic ILI coding. From analysis of influenza outbreaks, relative timeliness could be improved in 92% of regions with access to both systems, with more information provided in areas where only one type of facility exists.