What is Viral Fitness and How is it Measured?

[dsterncardinale]

I’ve responded to that piece at length. Short version: I’m right and they’re wrong. One of the parts of the H1N1 paper I quoted above, which I will repeat below, bears out my criticism:

@dsterncardinale

Regardless, general attenuation due to genome-wide mutation accumulation might best explain the very low mortality [54] associated with the 2009 pandemic. The earliest 2009 outbreak strain had already accumulated 1,889 mutations compared to the 1918 strain.

Emphasis mine. They’re counting it as a single lineage.