^ I'm not sure why a mutation would possibly kill the virus. Wouldn't just some of the viruses mutate, and the rest of the CoV's NOT mutate and continue infecting people -
There's two types of viruses- RNA and DNA.
DNA viruses are composed of a double helix that is "self-checking" pair structure. When the virus is using a cell to generate copies, a serious error causes that copy to be incapable of exiting the cell.
RNA viruses are a single string without that self-checking mechanism. The copying process generates frequent errors and a lot of unusable failures.
Coronaviruses are RNA viruses.
It's not that these copy errors and failures are "killed". A virus always reminds me of chain letters that we used to do in high school where someone sends a letter in an envelope to you. You open the envelope and inside is a letter that says you have to make 5 copies and mail them out. Some people make the copies. Some don't. Some people make errors when they're copying (whether they hand-write, type or photocopy the letter). Some people do the letter but never get around to mailing them. Some people do the letter but get the address wrong, so it never gets to the next person.
As long as at least 1 person makes the 5 copies and successfully mails them, then the chain letter continues to grow... and any spelling errors or crappy photocopies included get passed on to the next person.
This video explains why successful viruses tend to generate less-beneficial mutations and why this coronavirus is not producing a lot of mutations:
^ - or perhaps undergo a different mutation that may be more lethal, as what happened to the Kansas Flu in 1918? (usually erroneously a/k/a The Spanish Flu)
The 1918 influenza and the swine flu of the 1970s were H1N1 viruses which is a bird flu that also affects pigs. When it crosses over to humans it causes severe disease. The problem with the 1918 virus was not that the virus was so lethal. The problem was that its mutate was novel enough that the younger population had no innate immunity (either from previous infection of a different H1N1 strain) or because their genetic immunity passed from their parents lacked an exposure.
The novel nature of the 1918 strain triggered an auto-immune response- just like COVID-19 and other novel viruses. Because the people who contracted the 1918 influenza did not have immunity, their immune systems triggered a massive storm of responses that caused pneumonia, clotting disorders, dehydration and other auto-immune phenomenon that proved to be lethal at a time when people couldn't be saved with ventilators and fluid resuscitation.
Influenza is endemic in humans- it's always being circulated in the background with seasonal flare-ups. Strains of influenza that make people less sick get circulated more (think: coworker who feels crappy but doesn't want to use their sick leave) and tend to overrule strains that make people take to their bed (or occasionally, end up in a coffin). H1N1 is still in circulation but we don't see outbreaks of it very often because the other strains that are more contagious and make people less sick then to overrule the strains that make people really sick.
Unless, possibly, the virus is predisposed to a SPECIFIC mutation which will tend to routinely happen...like the common cold, which is also a coronavirus, has like 200 different variations. Isn't the flu (or most of them, at least) also a coronavirus?
Just curious, do a lot of the cold virus variations have a common ancestor? I'm not sure if anybody knows.
The "common cold" is actually a bunch of different viruses and strains of those viruses that have similar symptoms. We "get a cold" probably 1-5 times a year and most of the time, we don't get very sick and we have no idea which common cold virus we had.
The most common "cold" viruses are rhinoviruses. Probably 10% of colds are coronaviruses (about the same percentage as influenza "colds"). Because they are relatively a small percentage of cold viruses, it is possible that a person could have a lifetime of colds but only contract a coronavirus a few times in their lifetime, if at all.
Of the different coronaviruses, there are 4 species that fall under the "common cold" umbrella of diseases. Coronaviruses aren't natural matches for humans which is why the 4 species that are endemic in humans cause mild symptoms. Coronaviruses seem to be more natural matches for bats where they either cause no symptoms or they affect the gastrointestinal system of the bat. The coronaviruses that cause SARS, MERS and COVID-19 are recent crossovers from bats that passed through another animal that is more likely to be in contact with humans and because they are new (or "novel") to humans, they can cause severe disease.
