Will future variants of Sars-Cov-2 tailor themselves to target the vaccinated? Given that up to 90% of the population of some countries are now fully vaccinated, the question should perhaps be: Why would Sars-CoV-2 NOT target the vaccinated?
Selective pressure on the virus may mean an increasing drift towards variants that can overcome vaccines, as we are already seeing with Omicron.
There is some evidence in the scientific literature that the global vaccination campaign may have, through selective pressure, encouraged the virus to target the vaccinated.
- In this Medrxiv preprint, “COVID-19 vaccines dampen genomic diversity of SARS-CoV-2: Unvaccinated patients exhibit more antigenic mutational variance”, the authors state that “This study presents the first known evidence that COVID-19 vaccines are fundamentally restricting the evolutionary and antigenic escape pathways accessible to SARS-CoV-2.”
- In this PLOS paper, the authors assert that there is a “risk of rapid evolutionary escape from biomedical interventions targeting evolution”, and “predicted resistance timelines are comparable to those of the decay kinetics of nAbs raised against vaccinal or natural antigens, raising a second potential mechanism for loss of immunity in the population.”
- In this Frontiersin.org paper, “Implication of SARS-CoV-2 Immune Escape Spike Variants on Secondary and Vaccine Breakthrough Infections”, the authors state: “The increasing degree of immunity in the human population is inevitably conferring a great deal of selective pressure on the virus that promotes the rise of antibody escape mutants. The emergence of immune escape mutants is perhaps most apparent in chronic COVID-19 patients as documented in multiple reports.”
- This UK government paper suggested ways in which Sars-CoV-2 may evolve in future: “Antigenic ‘shift’: Natural recombination events that insert a different spike gene sequence (or partial sequence) from human CoVs MERS-CoV… This would recombine into the ‘body’ of SARS-CoV-2 that is capable of high replication in human cells. The consequence could be a virus that causes disease at a level similar to COVID-19 when it first emerged but against which our current battery of spike glycoprotein-based vaccines would not work.
- In this Virolyvj paper, the authors say “we speculate that with continued circulation, vaccination and convalescent sera therapy, further positively selected for mutations in the NTD are likely to occur.”
Shown below, there certainly seems to be a bias towards infecting the vaccinated in the daily case figures from Denmark’s SSI. Double and triple vaccinated individuals were making up ~90% of all new daily cases recently.
Shown above, from the latest Danish report for vaccine breakthrough infections, it is clear that the vaccinated make up far more of new Covid cases than the unvaccinated.
Shown below, nearly 300,000 cases of Covid are vaccine breakthroughs for those with two doses, and nearly 35,000 cases are breakthrough cases for those with three doses.
Clearly, Sars-CoV-2 will become under ever greater selective pressure to infect the vaccinated as the pool of unvaccinated people decreases. Deliberately targeting the vaccinated cohort may be the only possible way for the virus to survive in future.
You may not feel comfortable with the issues this post deals with, but if you haven’t considered the key question in this post – Could Sars-CoV-2 start targeting the vaccinated? – then you simply haven’t been paying attention for the last two years.
Selective pressure forcing Sars-CoV-2 to target the vaccinated is not only a possibility, with the Omicron variant, it may have already started.