Figure 3

Five distinct temporal patterns govern how the pandemic flu spread throughout the US. The normalized temporal amplitude is plotted against the total number of days (Apr 1, 2009-Mar 31, 2010). Observe the distinct lag in each of the five patterns, with successive H _i indicating the peak shift occurring towards the left (indicted by a gray arrow). These patterns summarize the different peaks during the H1N1 pandemic. Notably, H₁, H₄ and H₅ capture the late, middle and early H1N1 pandemic peaks occurring within the entire country.