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The current PCR tests detect three different regions of RNA that are expected to be relatively well conserved, so there's no single mutation that can cause PCR
by makomk 5y ago
The current PCR tests detect three different regions of RNA that are expected to be relatively well conserved, so there's no single mutation that can cause PCR tests to not detect them and we'll hopefully get a substantial early warning that allows the tests to be adapted if they ever head in that direction. One of the three markers detected by some of the PCR tests is actually invalidated by Omicron and some other variants but it's likely either bad luck or the result of some other benefit this mutation gives the virus. In order to get much benefit the virus would basically have to dodge all the things the PCR tests check for at once and that's hard to evolve.
- rich_sasha 5y agoYeah, Alpha had the same mutation as Omicron too. I'm not a virologist by any stretch of imagination. Mutations seem to come in bundles; I'm just surprised that, given typical PCR tests only test for three RNA fragments, that we don't see mutations that evade it. The main evolutionary pressure on Covid in developed countries is Public Health clamping down on it like a ton of bricks. A variant that quietly evades PCR tests, self-isolation etc. is set up for life.