[WaltPurvis]

You linked to the estimate of one scientist. It's stretching things to say "scientific agreement" with the implication that there's a consensus in the narrow band of 60-70% based on a data set of one.

I've seen estimates quite a bit lower than that, like 20%.

Although it is disturbing that 20% is about the lowest estimate I can recall seeing. I don't believe there are many (or any) scientists saying this will be a minor blip that only infects 1% or fewer. And 20% would be devastating, let alone 60-70%.