“there were no serious cases among first hundred or so infections”
That is very close to being true of the original COVID. Outside of the elderly, it has maybe a 1/1,000 death rate, so maybe 1/100 serious cases? Tops? The only guy I know who died supposedly from COVID had a heart attack 10 years early and was told he’d be lucky to live 5 more years. And 10 years later...he died “from” COVID.
It will require tens of thousands of cases to determine if Omicron is dangerous because COVID just isn’t a very dangerous disease!
We'll know soon enough, surely within a month.