Julian wrote:monabri wrote:So, this massive surge in positive tests cases must, in the majority, be Delta.
I’m not convinced your conclusion is correct. My eye is drawn towards the phrase “confirmed omicron cases”. I assume here that confirmed means a positive swab has actually been sequenced as opposed to simply displaying S-gene dropout which wouldn’t merit “confirmed” but rather “strongly suspected” or “very likely”.
Something seems very wrong here. Important information is not being used.
What we need is not the number of confirmed Omicron case, but the number of confirmed Omicron cases AND the number of confirmed Delta (and others) cases. Assuming random sampling or testing everyone of whatever population they decide to sequence that should give a good idea of the prevalence of each strain. The same can be done with the S dropout for "suspected cases". The number of S dropouts detected v. the number of tests that could detect the S dropout but don't.
There would still be a lag, but not the nonsense of saying "40 confirmed Omicron cases". There's a big difference between "We sequenced 41 cases and 40 of them are Omicron" and "We sequenced 4000 cases and 40 of them were Omicron."
* And dammit they should be doing random sampling. This type of surveillance is by far the most valuable use of tests, at least of the first few thousand a week.