Objective: After initial flu cases are reported, months elapse before vaccine becomes available. The authors report the experience of US states during the fall of 2009 on H1N1 vaccine availability in relation to the occurrence of disease.
Design: The authors used data from the Centers for Disease Control and prevention and state health departments to approximate second wave H1N1 epidemic curves. The authors compared these curves to two sources of vaccine distribution data-shipment and administration.
Results: Ten states received their first shipments of vaccine after the epidemic peaked, four states during the week of the peak, and 10 states only 1 week prior to the peak. In nearly half of all states, the epidemic had already begun to decline before any individuals could have been protected.
Conclusions: A sensible approach would be to highlight the importance of diligent hygienic behavior and to reduce the rate of human-to-human contacts before vaccine is available.