Of interest to IPA investors...There is growing evidence that Omicron may have evolved in an animal population (namely mice) before a human acquired the virus in SA.
Omicron is such an outlier to the original strains up to and including Delta, that there may not be another plausible theory as to its sudden apperance.
If that is the case it seems to me that we need solutions that account for transfers to and from animal populations. Such as polytrope solutions perhaps?
https://www.medicalnewstoday.com/articles/covid-19-did-omicron-evolve-in-mice