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That article is a bit outdated already...
BA.2.75.2 is just BA.2.75 with R346T and F486S. The XBB recombinant encompasses all of BA.2.75.2's mutations plus L368I, V445P, and F490S. BQ.1.1 is BA.5 with R346T, K444T, and N460K. All of these are escape mutations, that is, intended to escape neutralizing antibodies, specifically the ones that are still conserved from the original Wuhan-type virus.
It's clear now that the next dominant strain will be one of these two and not one of the other BA.2.75 or BA.5 lineages:
The daily advantage of BA.5 over BA.2 was ~ 13% a day so looking like one can expect a similar sized wave plus seasonal effects.
But at least the Singaporean MOH just divulged that XBB has a 30% lower chance of hospitalization than BA.5.
