agforlife97 said:
ttha_aggie_09 said:
Informative - Thanks!
Quote:
Roberto Burioni, a physician and professor at Vita-Salute San Raffaele University, in Milan, has been called the most famous virologist in Italy; he has written about the prospects for a "final" variant, a version of the coronavirus that has reached maximum transmissibility, and which becomes "the dominant strain, experiencing only occasional, minimal variations." As Burioni sees it, there are three potential futures for the coronavirus. The firstthe most optimistic for usis one in which the virus simply can't evolve its way around the vaccines. This is not an unlikely possibility. Many virusesmeasles, mumps, rubella, polio, smallpoxhave never meaningfully circumvented their vaccines, and so far the best of our current jabs have remained remarkably protective against new coronavirus variants, including Delta.
A second possibility is that the virus will partially evade our vaccine-generated immune defenses while paying a price, becoming less infectious or lethal. In order for the coronavirus to hide from our antibodies, it has to change aspects of the key components recognized by our immune systems, including the spike protein; those changes could end up diminishing the protein's ability to bind to the receptors it needs to infect cells. We can consider, for example, the Beta and Gamma variants, which exhibit some level of immune evasion but haven't become as infectious as Alpha or Delta. In the nineteen-nineties, H.I.V. experienced such a fate, when it hit upon a mutation known as M184V, which conferred resistance to the antiviral drug lamivudine. On the surface, this was a setback, but doctors soon learned that patients with the M184V variant had lower viral loads, suggesting that the mutation also reduced how efficiently the virus replicated inside the body. It became common for patients with H.I.V. to continue taking lamivudine even after resistance emerged, in part to select for the variant with a lower replication rate.
The third future is the most concerning: the virus could accumulate mutations that allow it to circumvent immunity without suffering a major reduction in transmissibility or lethality. This would require it to open up a new evolutionary spacea citrate moment. Even in this scenario, Burioni told me, we're in a fortunate position: we can quickly modify our vaccines to confront new variants. At the same time, the manufacturing and distribution challenges facing those variant-specific boosters would be colossal; we're struggling to fully vaccinate even a quarter of the world's population with the vaccines we already have.
The part in bold sure seems like what Delta is doing now, no?
The second option could already be happening. I'm not sure we have any way to tell whether delta is less deadly on its own or if it's less deadly because of the vaccines, or a combination of the two. The current wave has deaths about 1/5 of the previous two waves.
It is a sad thought but there is also a literal survivorship bias at work across the population.
We still don't seem to understand how much of the vulnerability is genetic. OTOH, if it is all age and lifestyle driven co-morbidities then those people pass but new vulnerable people may replace them.