Here's something that's been bugging me. The SIR (and SEIRS) model that this game is based on seem to me to have a flaw. Now obviously I'm not an epidemiologis

Here's something that's been bugging me. The SIR (and SEIRS) model that this game is based on seem to me to have a flaw. Now obviously I'm not an epidemiologist, and I'm sure that epidemiologists have a good handle on this, I just don't know what it is. The problem is this: if you assume an exponential decay, you're saying there's no point after infection at which the probability of transmission is zero. Probability of infection has a half-life in SIR. But for a virus like covid, we know that's not true: if you're infected, give it six weeks and you won't be infectious any more, one way or another. If you replace an exponential decay with a finite transmission lifetime, you do end up with different epidemic curves: they have steeper fall-off, for instance. What's the reasoning here?