It has happened before multiple times, so clearly it can happen. This feels like confusing weather and climate, and working backwards from a conclusion. The e

It has happened before multiple times, so clearly it can happen. This feels like confusing weather and climate, and working backwards from a conclusion. The evolutionary chance to make a single virus so well suited to human hosts is probably very small. If you take a single event and work backwards it seems very unlikely. But in aggregate over time, it'll happen fairly regularly, hence the warnings.