Faced with a national influenza vaccine shortage in fall 2004, the Anne Arundel County (Maryland) Department of Health was forced to alter plans for influenza vaccine distribution to reach County residents most at risk. While approximately 37,000 doses of vaccine had been ordered and were to be administered through 17 large flu clinics, only 8,000 doses of flu vaccine were now available for distribution. This year's vaccine shortage provided an opportunity to test the Department's capacity to mobilize mass clinics in the event of a natural emergency or bioterrorism. Implementation of Incident Management System and utilization of partnerships with County and State agencies and media proved that the community's readiness relies on the quality and training of the local public health infrastructure.