The question seems to have been finally put to bed. Some people were reported to be returning positive tests some time after recovering, but it seems the tests were reacting to inactive fragments of virus that were left in dead cells in the lungs, and these fragments were being released and detected as the cells broke down.
Other research on monkeys has shown that they have a very solid immune response that is protective. There seems little reason to think we won’t.
Luckily coronaviruses don’t seem to mutate very fast, and are not subject to recombination like the influenza virus.
So, overall, the smart money is on the virus behaving reasonably normally. At least in these respects.
It is all about the genome. The individual virus dies, but if the host infects others, the virus genome survives. The advantage not killing your host is that you get a better chance of living on in another host. No different to evolutionary advantages for any species.
That seems to be a binary choice between instant death and final death.
For example, let’s take two strains of a virus. Both have an incubation period, then a period of time where the person is symptomatic, going out in public coughing and sneezing and spreading, also spreading to his family members at home.
Then after that, the person goes to bed and the first virus ends up killing him but with the second virus, he recovers.
Both still had an equal opportunity to spread. Why is the killer one disfavored by evolution?
If anything, the killer one would spread more because instead of lying in bed for a few days and getting better, the person who dies would likely end up being transported to the hospital and infecting medical personnel, other staff, and other patients.
My gf’s brother just phoned us. He’s making a brisket and he asked if we wanted to come over for a picnic. We were actually surprised by the invitation, as he is an intelligent guy. Turns out in his circle of coworkers/friends, everyone is talking about how the virus thing is over.
On speakerphone we explained our POV. His wife works in a nursing home. A nursing home. The kind with old people packed into a poorly maintained structure and minimal PPE. Yeah, we’re staying home today.
Ultravires, coronaviruses are typically transmitted through air droplets. Imagine two versions of the virus – one kills you within 20 minutes of inhaling infected droplets and the other one has no symptoms and never kills you, allowing you to spread it indefinitely until your immune system can defeat it.
Which one would spread further? Obviously, the benign one that doesn’t even slow you down. The deadly one would have very few opportunities to spread – let’s say it sprang up in a crowded stadium – massive deaths! Then, it would be burned out, since all the hosts would be dead and no longer breathing, so unable to spread it further.
I wonder what your gf’s brother’s response will be when the number of cases shoots back up in your community. Will he be surprised? Will he wonder if they’re been lied to?
I can understand the “Fuckit, if I’m going to get the corona, I’m going to get the corona” mentality. I don’t agree with it, but I understand it and can even kinda-sorta sympathize with it. But I don’t understand the “The virus thing is over!” attitude by otherwise intelligent people living in the US. I want it to be over as much as the next person, but I’m not seeing any empirical evidence that it is over.
Remember Covid-19 only kills 1% or so of its victims–and 99% or so survive. So I just don’t see a significant advantage in spreading for a Covid-19 strain where 100% survive.
Saying that covid has a 99% survival rate is misleading even though it might be true. The survival rate for different groups is vastly different. Some groups may only have an 80% survival rate, some 90% and some 99.99%.
Different parts of the world will have different timing of whatever waves they get. Germany is basically over their first wave regardless of the situation in Somalia.
This Great Courses lecture does a good job explaining the course of the Spanish flu. The first wave was mild. Then the virus mutated. The second wave was a killer of unprecedented proportion.
The outcome of this would be that the hospital ceases to function, and can no longer spread the virus, or the hospital would protect itself by refusing to accept the most dangerous cases. It also bears mentioning that much of humanity lacks access to hospitals or medical transport.
Either way, the general evolutionary principle holds. The most successful pathogens trigger a lot of shedding behavior (sneezing, coughing, etc) but allow the host to continue routine exposure to other hosts. This is why the common cold is virtually indestructible; often it’s so mild that people can’t justify missing work, school, etc.
Yes, the lecturer gives a lay cursory overview of flu viral mutation and the likelihood the Spanish flu mutated this way in this lecture. He goes into more detail in a later lecture (but, that isn’t free). The 3 free lectures available are worth watching, however.