Originally Posted by Greedy,Greedy,Greedy
Here is the story on viruses mutating as I understand it from talking to some extremely bright people* about things I'm not trained to fully understand.
Viruses mutate all the time, but RNA viruses like flu have mutations that survive much more often than retroviruses like AIDs that directly impact DNA. What viruses do - invade cells and replicate - is really pretty extraordinary, so most mutations for any virus are likely to render the mutated form ineffective and those mutations just die, but some mutations still replicate and those survive. For flu, a fair number of mutations survive and that's a big part of how we have annual flu cycles. Hopefully, those that do survive can be treated with the same vaccine - the great fear among flu vaccine specialists is a mutation that renders the virus less treatable with existing vaccines or with vaccines developed with existing methods and approaches, regardless of the "strength" of the mutated virus.
But in other viruses fewer mutations survive. AIDs is an example of a retrovirus, a virus that triggers on to a cell's DNA and not just RNA, and retroviruses in general have many fewer mutations survive at all, so we're treating the same AIDs virus strain now as we were 25 year ago.
But you can't count on mutations to "weaken" a virus; when a mutation occurs, antibodies developed in reaction to early strains or vaccines may still work on the mutation, but not always. If you have a virus that does a ton of damage, it is more likely that a mutation will be less damaging, just because viruses that do a ton of damage are relatively rare, but if you have a virus that doesn't do much damage, there may be a better chance the mutation will do more damage, because if its really weak it may not be able to get much weaker. The strong viruses all come out of somewhere.
The big question though is whether the virus can do an end-run around your immune system and the defenses its built against other viruses, and that matters more than some inherent "strength" of a virus. This is part of why viruses that jump from other animals often do a job on us - we haven't developed any natural defenses over time. When they mutate to attack human cells as well as, for example, pig cells, they have a new host who doesn't fight back. It's also why things like AIDs and Coronavirus, which only show up now and then in human history rather than every year in new forms, are more damaging to us than flu viruses, which form a larger interrelated family that feeds on us regularly. So what's more important than the virus' strength is our own susceptibility. Too many mutations of a relatively novel virus like CvD 19 could be a big problem for us, because we are more susceptible than we would be for a flu virus. Small mutations of things we've already been exposed to are usually less damaging to us because they are controlled by the same antibodies we've already developed, not because the viruses themselves are somehow always "weaker".
I'm sure if we had an epidemiologist on the Board they'd want to fix up a lot of this, so take it all with a grain of salt. The bottom line for me is that we still need to know a lot about this virus, and I have people I work with who come out of both the flu vaccine and aids vaccine worlds working on CVD 19 because it is a kind of "in between" case - it is an RNA based virus like the Flu but also has some retrovirus characteristics like AIDS.
* may include a number of Nobel prize winners, which perhaps means I should have a Noble prize.
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