Malsua |
07-28-2021 02:50 PM |
Quote:
Originally Posted by Robbie0723
(Post 1979549)
Interesting point, the varients seem to surge and burn out once the next more infectious varient takes hold.
Do these mutations have any effect on the accuracy/sensitivity of the COVID tests?
Anecdotally, I'm seeing more vaccinated family/friends getting and recovering upper respiratory symptoms but are COVID negative.
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As has been said above, viruses tend to mutate towards more contagious and less deadly. If they go the other way, they will either stop spreading or kill their hosts too fast. Whichever variant infects more wins the game. You infect more by being more contagious and letting your host live longer.
The Spanish Flu of 1918 is around today and if you ever got a seasonal flu shot, chances are you got a vaccine to prevent it. It is no where near as deadly as it was back then.
At this time, there have only been slight variations in the genome. A few proteins have changed, like the aforementioned proline to arginine. These minor variations do not affect the accuracy of the test.
If you've heard of the PCR test, this is a polymearse chain reaction test. It works by amplifying the sample and comparing it. If it doesn't find a match, it amplifies it again. This is called the cycle threshold. Typical PCR tests should stop looking at around 30, maybe 32 cycles. Beyond that, you're probably amplifying viral fragments rather than a viable virus. One of the complaints is how far out they are running the CT(I read 40 in Canada!) because it's not very meaningful, specially if a patient is not symptomatic. I.e. lower CT, means that there is less amplification and more virus to detect.
So to answer the question, does the variant affect the accuracy? Well, I can tell you that on positive delta variant PCRs the CTs are 4-8 cycles lower. While not "accuracy", it's certainly a better indication of a case because the viral load is much, much greater. That said, even with the higher viral load, the actual disease presentation, in general, is not as bad. This is not to make light of it, people will still die, but not nearly to the same degree as the original.
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