> Is it possible the Delta variant itself was somehow the result of our intrepid and swift vaccination efforts?
The variants can arise under neutral genetic drift, ie pure random chance via naturally occurring mutation.
But the widespread dominance of these variants is very plausibly connected to the mass vaccination efforts.
Here is another good paper on the subject, in case you haven't already seen it [1].
> I’m having a hard time understanding why more people aren’t talking about this
Me too, but to be fair these are complex second and third order effects that only gained traction in the scientific literature within the past decade or so. Right now everyone is mostly focused on first order effects - eg "will the vaccination help/harm me?"
Quotes from [1]:
- "Our modeling suggests that SARS-CoV-2 mutants with one or two mildly deleterious mutations are expected to exist in high numbers due to neutral genetic variation, and consequently resistance to vaccines or other prophylactics that rely on one or two antibodies for protection can develop quickly -and repeatedly- under positive selection."
- "Our work suggests that it is likely that standing genetic variation alone has already produced a substantial population of viruses with single and double nucleotide changes that confer nAb resistance. These variants will establish quickly in the population under selection pressure. In fact, there is already a precedent for this behavior, as one such selective sweep occurred early on in the SARS-CoV-2 pandemic when the D614G mutation rose to nearly 80% frequency in under 6 months [33]."
So this makes it sound like we might be headed for semi-annual or even quarterly boosters.
“one possible solution to the problem of immune evasion by SARS-CoV-2 that has been proposed is to develop a new vaccine update every year, similar to influenza [42]. In practice, such a solution will only work in the face of a moderate pace of evolution of SARS-CoV-2 and a low degree of clonal diversity among various clades of SARS-CoV-2 as they evolve to evade the current crop of vaccines. Further, if within-host evolution of SARS-CoV-2 contributes to population-level immune evasion, the valley-crossing mechanism described in this paper could accelerate the emergence of vaccine-resistant strains in the months following vaccine deployment. To the extent that new strains of SARS-CoV-2 are antigenically distinct, this may also lead to increased risk of antibody-dependent enhancement (ADE), as one mechanism for ADE involves antibodies that bind to the pathogen but fail to neutralize it [43]. Finally, our work suggests that immune evasion requiring one to two mutations occurs within months, raising the prospect that this phenomenon will further shorten the duration of natural immunity, which is already limited by the relatively short duration of the humoral [44,45] and cellular [46] responses to SARS-CoV-2 infection. Further studies are required to understand the risk immune evasion poses to a strategy of annually updated vaccines.”
I wonder if this is why Dr Fauci is emphasizing the need for therapeutics as higher priority than vaccines at this point? I should say though, mathematical biological models like the ones in this study are not something I feel very well equipped to evaluate. How often are such models wrong? What are the incentives for the company associated with these authors, “Fractal Therapeutics”? Obviously Harvard is Harvard, but I just can’t understand why smart people aren’t talking about this stuff. Murti-Bing pills?
> Is it possible the Delta variant itself was somehow the result of our intrepid and swift vaccination efforts?
The variants can arise under neutral genetic drift, ie pure random chance via naturally occurring mutation.
But the widespread dominance of these variants is very plausibly connected to the mass vaccination efforts.
Here is another good paper on the subject, in case you haven't already seen it [1].
> I’m having a hard time understanding why more people aren’t talking about this
Me too, but to be fair these are complex second and third order effects that only gained traction in the scientific literature within the past decade or so. Right now everyone is mostly focused on first order effects - eg "will the vaccination help/harm me?"
Quotes from [1]:
- "Our modeling suggests that SARS-CoV-2 mutants with one or two mildly deleterious mutations are expected to exist in high numbers due to neutral genetic variation, and consequently resistance to vaccines or other prophylactics that rely on one or two antibodies for protection can develop quickly -and repeatedly- under positive selection."
- "Our work suggests that it is likely that standing genetic variation alone has already produced a substantial population of viruses with single and double nucleotide changes that confer nAb resistance. These variants will establish quickly in the population under selection pressure. In fact, there is already a precedent for this behavior, as one such selective sweep occurred early on in the SARS-CoV-2 pandemic when the D614G mutation rose to nearly 80% frequency in under 6 months [33]."
[1] Risk of rapid evolutionary escape from biomedical interventions targeting SARS-CoV-2 spike protein https://pubmed.ncbi.nlm.nih.gov/33909660/