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Comment by jacob019 | Hacker News Reader

It matches what we've been told all along, that the virus will become more transmissable and less lethal.

It's true that over time the best reproduction strategy for a virus is to becoming incredibly transmissible but invisible to hosts, but the virus evolves via random walk and the local maximum could be more transmissible but lethal after a long delay.

There's no guarantees with randomness, though on a decade-long scale we can probably be sure it will fade into the background.

The evolution might be random, but the environment it evolves in and human behavior in response to it is not random. It was my understanding that the latter function is why we expect the course to result in a more transmissible but less lethal virus.

The more lethal it is, the fewer opportunities it would have to spread.

Except Covid-19 has traditionally had a significant lag time between being infectious and showing the first symptoms

Ebola is lethal. HIV is so bad that several treatments had to be engineered.

It is lethal to humans, but not to the animals that typically carry it. Ebola didn't evolve in humans to become highly lethal, it evolved to cross species.

HIV in and of itself does not kill you. It destroys your immune system in a lengthy process that ultimately leads to opportunistic infections that kill you. This process can take several months to several years. Likewise, HIV crossed species to infect humans, it did not evolve it's capabilities directly in humans.

It is naive to think that Sars-Cov2 will evolve to be less lethal.

Now that you mention, SarsCovid2 might have originated in either a pangolin, a bat or a bioweapons laboratory, according to early media reports. I can't believe that I am being serious, but it is what it is.

This is a myth, or a misunderstanding. SARS-CoV-2 does most of its transmitting before serious symptoms develop. The severity of those symptoms has no bearing on the fitness of the virus. We should not expect SARS-CoV-2 to evolve to be less lethal.

https://twitter.com/BallouxFrancois/status/12768029785826795...

There are other pathogens which we would indeed expect to evolve to become less lethal. On the other hand, there are some which evolve to be more lethal, like Dengue.

I wonder if a viable strategy for a future pandemic outbreak might be to deliberately encourage less lethal mutations to survive by, for example, having lockdowns that apply to contacts, friends and relatives of someone who died only?

On the other hand, we will be fighting less lethal variants much less. Less lockdowns and other hard measures, vaccines will be targeted at the more deadly variants obviously. That will play a role too in the long run. But it could take longer as it's not a direct effect.

Long term evolution of the virus would do that yes, but there is no guarantee that any particular mutation go in that manner.

Alpha was just as deadly but more transmissible. While Delta was both more transmissible and more deadly for example.

Less lethal or more slowly lethal? HIV is no less lethal now than it was decades ago. It spreads without issues because it kills the host a few years after infection instead of immediately. But HIV is as much of a death sentence today for people who do not seek or do no have access to treatments as it was 30 years ago.

HIV is transmitted pretty slowly - it may take many years to be passed on from one person to the next. Therefore any decrease in lethality might take hundreds of years to happen.

Widespread use of treatments would probably also stop the selection of less lethal strains.

Who told you that?

There is no selection pressure for Covid to become less lethal. None whatever.

Furthermore, no human virus has ever evolved to become less lethal.

Unfortunately this myth is often used by those who would like us to let Covid keep on killing, in order to protect their cashflows and for ideological and political reasons.

> There is no selection pressure for Covid to become less lethal.

Isn't there though? Say Covid killed within seconds. Then it couldn't spread. The longer the host lives, the more other people it can infect. I would almost say that the opposite of what you wrote is true.

Length of time until death doesn’t mean a virus is less lethal.

Rabies effectively has a 100% death rate and it can take years for it to kick in. There are cases of people suddenly showing symptoms 5 years after initial exposure, and once that happens, your brain basically rapidly rots and you drop dead.

We have no clue what the long term effects of any covid variants are. We can only speculate.

It’s exactly the opposite of what you are saying. There is pressure for the virus to NOT become more lethal in less time. It’s the opposite of saying that there is pressure for the virus to become less lethal in more time.

Did the Spanish flu not evolve into our less lethal, seasonal flu?

I don't think so. I also don't know why the black plague (Yersinia Pestis) ended.

Wikipedia theories are as reliable as usual. (Not reliable)

Yersinia Pestis is a bacterium, not a virus, and it can be killed by antibiotics. It's not gone. It's still around in fleas that live on squirrels and rats. In the mountains near where I live, the squirrels have it, and people get it every couple years.

But that may or may not be what caused the black death in medieval Europe, in my view. There's reason to think it might have been a really nasty hemorhagic virus like Ebola. See: https://history.howstuffworks.com/historical-events/black-de...

Antibiotics hadn't been discovered when the black plague ended. The bubonic plague that can described today is not the black plague.

There had been several pandemics of black plague, but at some point it didn't come back. Why?

Maybe there was a bacteriophague virus which caused Yersinia Pestis to be lethal? (Hypothesis) But why would it be gone?

https://pubmed.ncbi.nlm.nih.gov/27281573/

Yes, this is correct. https://www.smithsonianmag.com/science-nature/will-coronavir...

This is incorrect - there is obvious selection pressure for lower lethality. But it's also absurd and inappropriately politicizing a scientific question to assert that only "those" with a malevolent agenda believe that the virus will ultimately become less dangerous.

It's believed that each one of the other coronaviruses which are now endemic "common colds" began as a more lethal pandemic, the last probably being in 1890.

https://www.theguardian.com/world/2020/may/31/did-a-coronavi...

These other coronas are different, mostly upper respiratory and don't target ACE2 deep in the lungs or other organs.

ACE2 receptors are all over the respiratory tract and the lining of blood vessels[1]

Yes, Covid is primarily dangerous when it manages to get deep in the lungs and cause pneumonia. It takes a week or two of being sick before it gets there. That's why you heard early in the pandemic how people were fine, until about day 7 or day 10 and then suddenly went to the hospital. Other coronaviruses can do the same thing. If you ever get a cold for 10 days, your immune system is probably pretty bad and you very well might get pneumonia. But you don't usually get pneumonia from the cold coronaviruses, because your body knows how to fight them off. When the 1890 coronavirus hit, no one had immunity and it was pretty deadly. But we have good immunity to that virus now (so we call it a common cold). As long as you can ramp up an immune response and kill it off before it gets a foothold deep in your lungs.

[1] https://www.asbmb.org/asbmb-today/science/051620/what-is-the...

No, you can’t say that it will, it’s completely false. There is no advantage for a virus that has the maximum transmission level in the asymptomatic phase to become less lethal.

Name a single virus that did this.

(Noting that we don’t know what happened to the Spanish flu)

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