What public health data would have been used to determine the need for such a program?

Imagine that you are a public health nurse, and you and your colleagues have determined that the threat of a deadly new strain of influenza indicates a need for a mass inoculation program in your community. What public health data would have been used to determine the need for such a program? Where would you locate public health data? What data will be collected to determine the success of such a program? How might you communicate this to other communities or internationally?