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The evolution of Covid variants???

  • 22-01-2022 11:46am
    Registered Users Posts: 6,415 ✭✭✭ sporina

    Hi folks, I am looking for some good solid info I can understand, no how Covid has evolved.. new variants etc.. and how it becomes stronger/weaker with time, immunity etc..

    Does anyone has a link to some good info?


  • Registered Users Posts: 5,280 ✭✭✭ Chris_5339762

    Didn't they think Omicron came from a long-infected AIDS patient?

  • Registered Users Posts: 18,573 ✭✭✭✭ cnocbui

    That appears to be touched on in that link I posted"

    Scott Ferguson, being a PhD in pharmaceutical sciences and a postdoc at the Harvard Center for Systems Biology.

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  • Registered Users Posts: 6,415 ✭✭✭ sporina

    thanks for your posts but not exactly what I had in mind.. just something general about how viruses loose potency with time/immunity/vaccines etc

  • Registered Users Posts: 686 ✭✭✭ MilkyToast

    This is a very simplistic explanation, but...

    Small errors (mutation) happen in genetic reproduction that change the structure of some of the proteins in a virus. Sometimes the errors change the way the thing virus interacts with is environment. If the change is positive (for the virus), giving it a slight advantage (ability to reproduce more quickly) over previous iterations, then it will proliferate more quickly and eventually become dominant.

    Omicron is more able to spread through smaller droplets that are expelled with normal breath and talking than previous variants, is more able to infect through nasopharyngeal (nose and throat) tissue and reproduce there, and is less likely to infect the deeper lung tissue and other tissues that cause the immune response and accompanying inflammation that makes people feel really rotten (and causes more complications). It also seems more likely to cause no symptoms at all, while still being able to reproduce and spread.

    It outcompetes previous variants because while the "S" protein is quite different from the previous dominant variant (delta), most of the other proteins (M, N, E) that make up the full SARS-CoV-2 virus remain relatively unchanged—enough so that they are recognised by the immune system when encountered again, anyway, allowing the body to quickly mount an immune response against either variant after infection with one (though we don't know how long for).

    That is also why immunity after infection is much stronger than immunity with a vaccine based on a single protein.

    A much fitter variant will eventually outcompete a previous variant so much that the previous variant becomes extinct (as is currently happening with delta, and as happened before that with alpha, wild type, etc).

    Though viruses tend to mutate to cause less severe over time, there's no hard and fast rule that says they have to. The nightmare scenario would be a mutation that causes the virus to be slightly more transmissible than Omicron, completely evasive of the S-protein-based vaccines, with a much longer infectious incubation period that causes much more severe disease/death than alpha/delta, because it would outcompete omicron and use us as vehicles for reproduction before killing us all (but that is very, very unlikely from where we currently are).

    “Of all tyrannies, a tyranny sincerely exercised for the good of its victims may be the most oppressive. It would be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated; but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." ~C.S. Lewis

  • Registered Users Posts: 412 ✭✭ marilynrr

  • Posts: 0 [Deleted User]

    You're probably gonna have to be a bit more specific. Viruses are extremely diverse with wide variety in behaviour.

    Also the idea that viruses lose potency over time is not really accurate. Any reduction in severity is usually down to host immunity. For context smallpox likely spread in humans for thousands of years but was still capable of serious illness and death.

  • Registered Users Posts: 6,415 ✭✭✭ sporina

    any virologists on here?

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  • Registered Users Posts: 226 ✭✭ cannonballTaffyOjones

    The question is will a new variant come along in a few months to throw us all back in PCR/antigen travel testing, pubs closing etc... ?

  • Registered Users Posts: 3,637 ✭✭✭ Apogee

  • Registered Users Posts: 18,573 ✭✭✭✭ cnocbui

    Bit late with that.