[tweetiepooh]

True but history does show that populations can "get used" to a changing virus (flu, cold) but these are (initially) devastating to groups for whom these are novel. It's not hard to extrapolate that something similar could happen with CV19.



Vaccines made against initial variants are effective to those variations encountered so far. So either they were designed more "generically" or mutations are small enough. If continuing changes are also gradual those infected say with delta may have enough response for epsilon, zeta and eta. Zeta infection "protects" down to theta and so on. (Lambda is quite a big (alphabetical) step from delta, maybe the others didn't emerge enough).



The problems come if the change is large so neither vaccine nor "learned" immunity has an effect and that variation causes major symptoms. Hopefully we have mechanisms in place to deal with another pandemic better in any event.