artis said:
Interesting story, someone who has had a previous infection and a double moderna dose should have been really well protected given natural infection presents the full genetic material of the virus to the immune system + the two dose moderna vaccine is a strong vaccine (higher dose per shot than pfizer) and also I read from clinical trials that moderna offers even better immunity for Delta than pfizer.
Could it simple be that those who have a very mild first infection as the man in the video don't develop a good immune response? Although I guess it depends from person to person.Anyway I am wondering when Covid could maybe mutate out of existence. Can't be that a virus can hit the jackpot multiple times in a row?
I understand natural selection is pushing it such that only the more antibody resistant variants can survive as well as the more infectious ones, but and this is the important part that I want to know, isn't there just a limited number of possible "states" or configurations the individual proteins and parts of a virus can assemble into and still be functioning ?
In other words I guess I am asking when will this "son of a B..." run out of options and reach it's career top after which there is only downhill.
Someone please correct me but IIRC for any organism the ratio of bad mutations to beneficial is something like 100:1 ?
Does this differ from larger organisms like animals vs small RNA viruses ?
The mutation rate is much higher for viruses but how about the ratio of beneficial vs deleterious?
It is an interesting case but one of the problems in relying on natural infection is the variability in the response, people respond very differently. In people who have very severe disease the virus actually attacks the immune system, destroying the germinal centres responsible for producing the T and B cells. This wouldn't be the case here, and so far the severity of the disease doesn't seem a good indicator of the immune response, apart from in the very severely ill. The variability however remains, and vaccines do produce a more predictable response.
It's really not a very reassuring story and there seemed to be a note of desperation in the attempts to support vaccination. I'm not sure it helped, we really have to learn to tolerate some uncertainty in the outcomes, we still don't have definitive answers, sometimes, I don't know works.
You're actually right about evolutionary change having limits, in fact RNA viruses do live on the edge of possibilities, with few mutations actually being compatible with survival. They make up for this with having very high rates of reproduction and not investing many resources in error checking the genetic material. This increases the risk to their offspring from mutations, but you only need a few to survive when you reproduce so quickly. I don't think you can expect natural selection to come to our aid to wipe out an organism, the selection is for variants that increase reproductive fitness. However while antibody avoidance does clearly offer fitness advantages its unlikely to be a good long term solution, our immune system, also the product of evolution, alters and refines its response to changes in the virus. So, for both us and the virus we need to consider all the other factors or at least those we know, that can change the nature of a disease.
While many biological organisms seem to have developed a sort of fetish for being unpredictable, we can still try. The virus needs a victim to reproduce, it needs time and then it needs to be transmitted to others in a viable form. We often fear diseases which strike people down suddenly, causing severe disease and rapid death, consider Ebola. However, from the virus's perspective this isn't a good strategy, the fact that people automatically limit their contacts when they are ill and the speed of death simply doesn't give the virus time to spread easily. The disease, because of what it does, has so far been restricted to relatively local outbreaks. Rather worryingly, the early outbreaks had a case fatality rate @ 80%, during the more recent outbreaks it was around 60%, it may be getting milder and that's not good. However, in principle a mild disease is less likely to alter people's behaviour or even evoke wider treatment or containment methods, Ebola might have missed its chance.
Remember, we have other Coronavirus diseases that have jumped species in the past and the ones that adapted well to their human hosts, spread globally and are still with us, they cause colds. We don't know much about what happened after the disease became established in humans, but it may be that what we are seeing now is a re-run of similar events in the past. The most recent was in the 1890's according to genetic studies and occurred alongside a pandemic of an unknown disease that killed around a million people, they described it as Russian flu. Now, children tend to be exposed to this virus when they are young and tend to avoid harm and with continuing exposure there is a very high level of population immunity and the disease it causes is usually mild. Note the qualifiers in that sentence "tend" and "usually", I expect we will have to learn to live with each other. This is quite a common view among virologists, but it is still a form of informed crystal ball reading and there are some viral diseases in which none of this actually happened.