This page has a nice, succinct definition of how the various kinds of mutations can contribute to influenza changes. In short, a percentage difference isn't tha

This page has a nice, succinct definition of how the various kinds of mutations can contribute to influenza changes. In short, a percentage difference isn't that informative. It matters greatly what is actually different: http://nieman.harvard.edu/Microsites/NiemanGuideToCoveringPandemicFlu/TheScience/HowFluVirusesChange.aspx http://nieman.harvard.edu/Microsites/NiemanGuideToCoveringPa...