DO VACCINES INCREASE THE RISK OF A MORE CONTAGIOUS VARIANT?
Short answer: they do relatively but not absolutely.
Long answer in the thread below.
1/N
Short answer: they do relatively but not absolutely.
Long answer in the thread below.
1/N
2/ There are indications from previous research that the vaccinated tend to select for strains that resist vaccines (probably) and for more dangerous strains (perhaps).
But, this is in relative terms. What we care about are absolute ones.
quantamagazine.org/how-vaccines-c…
But, this is in relative terms. What we care about are absolute ones.
quantamagazine.org/how-vaccines-c…
3/ Vaccines help our immune system kill viruses faster. This is important because the less a virus reproduces, the fewer chances it has to mutate.
Probably, this means that the vaccinated are *relatively* more likely to produce dangerous strains but *absolutely* less likely.
Probably, this means that the vaccinated are *relatively* more likely to produce dangerous strains but *absolutely* less likely.
3B/ (Perhaps not even relatively, given that a vaccinated host kills the virus particles inside him faster, giving it less chances to reproduce and this to mutate.)
4/ In other words, is a country with 100 COVID cases, all vaccinated, more likely to produce a dangerous variant than a country with 10k cases, all unvaccinated? I don’t think so.
The latter has more shots at the “dangerous variant” roulette.
The latter has more shots at the “dangerous variant” roulette.
5/ The question is not if a dangerous variant is more likely to emerge from a vaccinated individual.
It's if it is more likely to emerge from a vaccinated POPULATION (that has way less virus circulating and reproducing compared to an unvaccinated one).
It's if it is more likely to emerge from a vaccinated POPULATION (that has way less virus circulating and reproducing compared to an unvaccinated one).
6/ Now, some frequently asked questions.
7/ Don't we only need one variant that's has learned to avoid vaccine defenses to create havoc?
Yes. But would it create more havoc than the original strain in the unvaccinated population?
(Also consider that the 2nd case would have more virus circulating → higher exposure.)
Yes. But would it create more havoc than the original strain in the unvaccinated population?
(Also consider that the 2nd case would have more virus circulating → higher exposure.)
8/ If viruses mutate into deadlier version when dealing with stronger immune systems (training grounds for the virus) and vaccines create more training grounds (hosts with strong immune systems) it should follow that vaccines accelerate deadlier mutations?
9/ No. If you bomb a battalion, you select for the strongest soldiers AND YET make the battalion weaker.
Same thing with vaccines: we might select stronger viruses but we make the pandemic as a whole way weaker.
Same thing with vaccines: we might select stronger viruses but we make the pandemic as a whole way weaker.
10/ Why didn’t dangerous variants emerge from smallpox and polio?
Part of it might depend by the viruses at hand, but consider that polio peaked at “just” 37 cases per 100k per year, smallpox at about 100 — fewer infections, fewer chances of mutating.
Part of it might depend by the viruses at hand, but consider that polio peaked at “just” 37 cases per 100k per year, smallpox at about 100 — fewer infections, fewer chances of mutating.
10B/ For comparison, COVID peaked at 120 times the prevalence of smallpox)
11/ "But Luca, stronger variants are over-represented in the vaccinated"
Of course, just like skillful thieves are over-represented in successful bank robberies.
But that doesn't mean that leaving banks undefended is a good idea – it would make robberies more frequent.
Of course, just like skillful thieves are over-represented in successful bank robberies.
But that doesn't mean that leaving banks undefended is a good idea – it would make robberies more frequent.
12/ Nor does it mean that defending banks makes thieves stronger. It simply prevents robberies by low-skilled thieves, and survivorship bias gives the appearance that it made thieves stronger.
Stronger thieves develop through mutation after successfully robbing the bank.
Stronger thieves develop through mutation after successfully robbing the bank.
13/ Stronger banks → less robberies → less chances of thieves getting more skillful.
Similarly, vaccinations select for stronger variants but doesn't create them – not any more than they would occur in the wild.
Same for vaccines → they make mutations less likely.
Similarly, vaccinations select for stronger variants but doesn't create them – not any more than they would occur in the wild.
Same for vaccines → they make mutations less likely.
14/ Disclaimer: I’m not a virologist (for example, I don’t think that a virus lab in a 10M city is a good idea), so I might not know some important piece of the puzzle. If anything is missing, please let me know.
15/ Conclusion: what matters is not the *relative* chance of, giving a variant developing, the chance it’s stronger.
Instead, what matters is the *absolute* chance of developing a stronger variant.
Instead, what matters is the *absolute* chance of developing a stronger variant.
16/ What matters is whether more people would die from a vaccinated population vs an unvaccinated one.
Due to the considerations of this thread, the answer is no. A vaccinated population is *more protected* against the risk of a new variant.
Due to the considerations of this thread, the answer is no. A vaccinated population is *more protected* against the risk of a new variant.
17/ In short: vaccination selects for immune escape variants, but doesn’t create them.
What creates them is mutations, and mutations come from reproduction. And viruses reproduce more in an unvaccinated population.
What creates them is mutations, and mutations come from reproduction. And viruses reproduce more in an unvaccinated population.
18/ A theoretical caveat. Given that it doesn’t appear to apply to current COVID strains, ADE seems to be an additional reason to vaccinate (to minimize the risk that a strain that could exploit ADE arises).
https://twitter.com/scmarco69/status/1418550466074615812
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