Punctuated Evolution of Influenza Virus Neuraminidase (A/H1N1) under Opposing Migration and Vaccination Pressures

Figure 6

A panoramic presentation of the opposing effects of migration and vaccination on NA roughness (variance of 𝜓(aa,17), MZ scale) after the first wide-spread vaccination program, begun by the US Army in 1944, as listed in Table 1. Flu virulence decreases or increases in tandem with NA roughness. The build-up of swine flu virulence from 2001 on is evident in selected urban areas (New York 2003, Berlin 2005, Houston 2007) with crowded immigrant neighborhoods. A few early error bars are indicated, but after 1986 these become too small for this sketch. The benefits of sustained vaccination programs shown here are large and are not easily recognized in short-term studies [42].