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0 pointsfer4y ago0 comments

First detection is an indicator of that, when it was first detected, not a guarantee that it was first there. Only a very small fraction of RT-PCR positive samples are sent for sequencing under normal conditions.

> Omicron COVID was in Italy as early as 2021-10-13 – 7 weeks before alarm from South Africa.

7 weeks before the alarm, but only 10 days before in retrospective sampling, and even less in other places in Africa.

Saying it appeared in Italy but somehow it spread in Southern Africa first goes against normal epidemiological dynamics, especially given how contagious Omicron is. The chances are it started where the first cluster is detected, not where the first retrospective case is detected, because the possibility of it escaping in Italy, flying to SA, and somehow staying dormant in Italy while giving SA a head-start is extremely unlikely.

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gojomo4y ago· 1 in thread

But Italy, hit extremely hard by early waves, and now with a much-higher vax rate than South Africa, could more easily miss a rising wave of mild cases in already-immune that don't seek treatment. There are plenty of factors in all directions, and only very spotty variant surveillance most places.

ferOP4y ago

South Africa has absurdly higher seroprevalence though, which generally provides higher protection.

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