The prior XBC.* surge in June-July was mostly from an unclassified evolution of XBC.1.3, involving a "frame shift" mutation in the Orf7a protein. It seems the virus dropped a fair chunk of that protein, which the experts speculate might have made it more efficient at replicating.

Speculative, but NZ and the regions of Australia the avoided Delta appear to be more vulnerable to "delatcron" variants like XAY and XBC?

The rapid cycling of very different variants implies increased immediate reinfection risks for those relying on immunity from a prior infection.

These variants are very rare outside of Tasmania, so people acquiring these variants will remain vulnerable to any other variant they encounter while they travel or that enters Tasmania in the coming months.

The flow of samples from Tasmania into GISAID stopped in May, so it's great to see it has resumed. Sample volumes look representative up to July 27.

Interactive genomic sequencing dataviz, code, acknowledgements and more info here:
https://github.com/Mike-Honey/covid-19-genomes#readme

🧵 end