shpalman wrote: ↑Mon Dec 21, 2020 9:34 am
I think it means certain PCR tests might be less sensitive to it, depending on which bits of the viral genome they're looking for.
Of course these tests won't tell you which variant they've detected; in the UK I think they've been randomly selecting
some samples for full sequencing and I suppose that in the Italian who came back from London and tested positive, they sequenced his swab to check if it was the new variant.
This site says the UK's covid genomics programme currently has full viral genomes for ~10% of all positive tests. I don't know how that compares to other countries, but it is a field where the UK does have top-notch capabilities, and I don't know if many countries are full genome sequencing at that scale. So there's a very strong chance that something like this has happened, or could happen, elsewhere, in a place that isn't looking so hard for it. I'm not sure how well the US is doing on this front for example.
https://www.cogconsortium.uk/news_item/ ... mutations/
On the question of sensitivity of tests to the variant, there are two questions - one is that the routine RT-PCR testing is a test
for the virus, but not for which specific variants, and the other is that certain mutants might fall on the PCR primer sites and so affect detection. The tests don't rely on a single primer pair, so should be able to see past that, but I did see a comment that this variant does cause a drop-out of one of the routine primers. (I presume this is at the two-codon deletion site, which is a more significant change in sequence than a single base change. )