I read people claiming that the first doses first strategy could cause evolution of the virus to escape the vaccine. Is there any truth to that? Does that factor into the cost-benefit analysis?
(From this retweet from a Prof at Geneva Centre for Emerging Viral Diseases)
Does not make that much intuitive sense to me because there are a lot of random mutations happening. If the first dose first (or first dose only) strategy reduces the size of the whole SARS-CoV-2 viriome, there will be fewer viruses and less genetic variation in total. More infections in total means more genetic diversity. More infections means that a vaccinated person will be exposed to more sources of infection, more virions, more different genomes over time, thus also increasing the likelihood of mutants able to escape the immunologic response.
Does that assume that the amount of mutations (and therefore the risk of an immune escape) is only dependent on the size of the viriome?
But isn’t it possible that the risk of an immune escape mutation in the 1-dose vaccinated population is much higher than in the rest of the population? I think if that was much higher, it could swamp the benefit of reduced overall chance for dangerous mutations occurring due to the reduced infections from vaccinating more people (as compared to 2 doses).
Not sure of any of this, just trying to think through your intuition.
A follow up thought: What do we know or what can we guess about the effect of 1-dose on reducing transmissibility? If we vaccinate twice as many, but they are still very much infectious (compared to 2-dose), could that be a problem?
I read people claiming that the first doses first strategy could cause evolution of the virus to escape the vaccine. Is there any truth to that? Does that factor into the cost-benefit analysis?
(From this retweet from a Prof at Geneva Centre for Emerging Viral Diseases)
Does not make that much intuitive sense to me because there are a lot of random mutations happening. If the first dose first (or first dose only) strategy reduces the size of the whole SARS-CoV-2 viriome, there will be fewer viruses and less genetic variation in total. More infections in total means more genetic diversity. More infections means that a vaccinated person will be exposed to more sources of infection, more virions, more different genomes over time, thus also increasing the likelihood of mutants able to escape the immunologic response.
Does that assume that the amount of mutations (and therefore the risk of an immune escape) is only dependent on the size of the viriome? But isn’t it possible that the risk of an immune escape mutation in the 1-dose vaccinated population is much higher than in the rest of the population? I think if that was much higher, it could swamp the benefit of reduced overall chance for dangerous mutations occurring due to the reduced infections from vaccinating more people (as compared to 2 doses). Not sure of any of this, just trying to think through your intuition.
A follow up thought: What do we know or what can we guess about the effect of 1-dose on reducing transmissibility? If we vaccinate twice as many, but they are still very much infectious (compared to 2-dose), could that be a problem?