At 5 a.m. on Sept. 30, the Centers for Disease Control and Prevention (CDC) will launch its largest vaccine giveaway in decades. Lining up for this invitation-only event will be the health departments of each of the 50 U.S. states, which are responsible for dispensing at least 251 million doses of the 2009 H1N1 pandemic-flu vaccine to health providers across the nation. The vaccines have been purchased by the Federal Government and will be given to states — and patients — gratis. It's not the usual way influenza immunizations are distributed, but nothing about this flu season is normal — from the dominance of a novel strain to the high number of cases emerging so early in fall to the creation and testing of an additional vaccine. So before you line up for your shot, here's the latest on the vaccine rollout.