This is a novel virus, supposedly.. whether totally natural or modified, it will absolutely be less fit the first time it encounters a new host species. That was last year. The past year has been it getting more and more familiar, comfortable, and capable in its new host species.. until it optimizes binding affinity and transmission, virulence is unlikely to go down..

In other words, it's going to get a hell of a lot worse and kill / maim a lot more people before that process gets underway. Nowhere near there yet.