Optimal allocation of pandemic influenza vaccine depends on age, risk and timing.

The limited production capacity for vaccines raises the question what the best strategy is for allocating the vaccine to mitigate an influenza pandemic. We developed an age-structured model for spread of an influenza pandemic and validated it against observations from the Asian flu pandemic. Two strategies were evaluated: vaccination can be implemented at the start of the influenza pandemic, or vaccination will be implemented near the peak of it. Our results suggest prioritizing individuals with a high-risk of complications if a vaccine becomes available during a pandemic. If available at the start, vaccinating school children might be considered since this results in slightly lower expected number of deaths.