3 ms·

It's going to mutate regardless of how many people are vaccinated. The entire point is to make it so that people don't have the runaway immune system responses

It's going to mutate regardless of how many people are vaccinated. The entire point is to make it so that people don't have the runaway immune system responses that are melting lungs and brains.

anyfoo 5y ago
Is that true? Intuitively, the more virus exists (in absolute numbers, even), the more virus may potentially mutate into worse variants. More infected people -> more individual virus instances, each with a given chance to mutate, and more time for that mutation to occur (because expired virus is replenished with fresh virus in available hosts; though you can probably fold this into higher virus numbers instead with the same result). I'm gladly corrected if I missed something!
- totony 5y ago
  Variant that achieve immune escape from vaccine-induced immunity are bound to propagate at a faster rate if most people are vaccinated. Even if that variant is more lethal (from which you might expect a smaller R0), it might be prevalent because of an augmentation in R0 from vaccination (which might be lesser had people developed a more complete natural immunity).
suchire 5y ago
The likelihood of mutation is directly proportional to how widespread a virus is multiplied by the amount of time it stays that way (more specifically, the area under the curve for infections over time). Vaccination and control of spread is critical to preventing further variants
- totony 5y ago
  Likehood of mutation might be, but spread of variants is a more complicated function. Vaccination for sure might affect how likely one variant predominates against others. Considering cross-immunization between variants with natural immunity, it might be more efficient to refrain from vaccines to give cross-immunity with a weaker variant.
- AndrewBissell 5y ago
  This isn't really true. For instance, it's been shown that mutations are far more common in immunocompromised people (many of whom cannot even take the vaccines) where the virus can just camp out for months and train itself against the human immune system. So one particular host might serve as a more fertile environment for variants than thousands of others combined. https://www.washingtonpost.com/health/2021/03/11/immunocompromised-patients-covid-variants/ https://www.washingtonpost.com/health/2021/03/11/immunocompr...
- jfoster 5y ago
  Doesn't this mostly depend on 3 things? 1. Likelihood of breakthrough infections. 2. Mutation rate. 3. Initial volume of infections. For instance, if the likelihood of breakthrough infections is low enough to overcome the reproduction rate, the mutation rate is slow enough, and the initial volume of infections low enough, you'd expect that the virus would die out if enough people have had the vaccine, right? On the other hand, if the likelihood of breakthrough infections were high, mutation rate were high, initial volume of infections high, makes sense that you would expect to see ongoing mutation. Another way I think this might go is that mutations happen & breakthrough infections happen, but the breakthrough infections further boost immunity, and the severity never re-approaches the original severity of covid.
- peytn 5y ago
  Only if you ignore the fact that viruses compete for hosts.

It's going to mutate regardless of how many people are vaccinated. The entire point is to make it so that people don't have the runaway immune system responses that are melting lungs and brains.

anyfoo 5y ago

Is that true? Intuitively, the more virus exists (in absolute numbers, even), the more virus may potentially mutate into worse variants. More infected people -> more individual virus instances, each with a given chance to mutate, and more time for that mutation to occur (because expired virus is replenished with fresh virus in available hosts; though you can probably fold this into higher virus numbers instead with the same result). I'm gladly corrected if I missed something!

totony 5y ago
Variant that achieve immune escape from vaccine-induced immunity are bound to propagate at a faster rate if most people are vaccinated. Even if that variant is more lethal (from which you might expect a smaller R0), it might be prevalent because of an augmentation in R0 from vaccination (which might be lesser had people developed a more complete natural immunity).

suchire 5y ago

The likelihood of mutation is directly proportional to how widespread a virus is multiplied by the amount of time it stays that way (more specifically, the area under the curve for infections over time). Vaccination and control of spread is critical to preventing further variants

totony 5y ago
Likehood of mutation might be, but spread of variants is a more complicated function. Vaccination for sure might affect how likely one variant predominates against others. Considering cross-immunization between variants with natural immunity, it might be more efficient to refrain from vaccines to give cross-immunity with a weaker variant.
AndrewBissell 5y ago
This isn't really true. For instance, it's been shown that mutations are far more common in immunocompromised people (many of whom cannot even take the vaccines) where the virus can just camp out for months and train itself against the human immune system. So one particular host might serve as a more fertile environment for variants than thousands of others combined. https://www.washingtonpost.com/health/2021/03/11/immunocompromised-patients-covid-variants/ https://www.washingtonpost.com/health/2021/03/11/immunocompr...
jfoster 5y ago
Doesn't this mostly depend on 3 things? 1. Likelihood of breakthrough infections. 2. Mutation rate. 3. Initial volume of infections. For instance, if the likelihood of breakthrough infections is low enough to overcome the reproduction rate, the mutation rate is slow enough, and the initial volume of infections low enough, you'd expect that the virus would die out if enough people have had the vaccine, right? On the other hand, if the likelihood of breakthrough infections were high, mutation rate were high, initial volume of infections high, makes sense that you would expect to see ongoing mutation. Another way I think this might go is that mutations happen & breakthrough infections happen, but the breakthrough infections further boost immunity, and the severity never re-approaches the original severity of covid.
peytn 5y ago
Only if you ignore the fact that viruses compete for hosts.