@Expat_tom -- suppression is a mathematical function. If you have a virus with an R0 of 2.5 then suppression is at 60% resistance. How you get resistance (infection, vaccination or pre-existing cross-reaction) does not matter. What matters is that once you get there the average person who gets it will not manage to infect another host, thus there is no exponential spread that will occur. That does NOT mean nobody will get it -- it simply means that it's like the flu, where there will be clusters here and there but the entire fucking town doesn't wind up in the hospital at once.

The formula is 1 - 1/R0 -- it's basic epidemiology. R0 is the theoretical transmission expansion in a 100% susceptible population. It is never actually realized because as soon as the first person gets the bug the population is no longer 100% susceptible. But -- because of how exponents work meaningful suppression does not start to show up until you're about halfway to the suppression rate, wherever it is.

Susceptibility is not a variable -- you either have antibodies or T-cell resistance or you do not -- but OUTCOME is.

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