> the much-more-contagious Delta and Omicron, neither of which would have realistically arisen at all if Omicron was an offshoot of Wuhan or Alpha, most likely

> the much-more-contagious Delta and Omicron, neither of which would have realistically arisen at all if Omicron was an offshoot of Wuhan or Alpha, most likely jump back from an animal reservoir to humans (rats being the best theory) - even though it came after Delta, it was not a descendant of Delta. Even if we'd completely wiped out the virus in humans by the end of 2020, it could still have happened. Deer, minks, cats, rats, and I'm sure I'm forgetting more - it was clear these animal reservoirs existed in 2020 and once we knew that, it was obvious to everyone except the experts that we can't eliminate this virus. There'd just be another spillover later. Oh, and a note on the "more contagious" part - Delta wasn't more contagious than what came before it. It's the common line but only works because the previous variants were revised downwards to make room for Delta. The earliest R0 estimate back in like Jan/Feb 2020 was 5 or 6, which was almost immediately revised downwards to 3 or 4 because that was seen as too high. Mid-year the estimate went back up to 5/6 for a short time, then at the end of the year when Delta was identified (but not yet named Delta), they gave the 5/6 range to Delta and put the previous variants back at 3/4.