With this Corona virus malarky going on, I stumbled onto this page, which gives a basic overview of tranmission simulations, and lets you play around by changing the transmission rate.
However, the 3rd interactive example, which illustrates SIS, under section "SIR vs. SIS" caught my eye.
(illustration below)
While playing around, I noticed that the virus dies out at around $20\%$ transmission rate. But the way I see it, it shouldn't die out at this rate.
Since (almost) every cell has $8$ neighbours, with a transmission rate higher than $\frac{1}{8}$, I would expect at least one of the neighbours to get infected. And this applies for all cells. Thus, since $20\%=\frac{1}{5}>\frac{1}{8}$ I would expect the virus to go on living. However, this does not happen.
i.e.
The expected number of infections, from one infected cell is $\approx p*8$, where $p$ is the transmission rate.
Ss my questions are:
- Am I wrong?
- Am I thinking about it in the wrong way?
- Is there something I'm missing here?
- Or indeed - we should se a different scenario, and there is something wrong with the simulation?
Thanks!