We don't know how many spillover events there were. Just just know that it's at least two. Most spillover events probably do not lead to a sustained outbreak.

We don't know how many spillover events there were. Just just know that it's at least two. Most spillover events probably do not lead to a sustained outbreak. The problem with positing that the mutations happened after spillover is that the timeline is way too short. Multiple variants were present at the market just weeks after the initial human cases. That points to differentiation before spillover, probably on the farms where the animals were being kept.