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I have a question for anyone who has a serious level of knowledge on virus evolution: As viruses evolve over time is there any correlation to severity - do the

I have a question for anyone who has a serious level of knowledge on virus evolution: As viruses evolve over time is there any correlation to severity - do they have trade offs as they evolve? I am hoping that it would be some kind of trade off that the virus makes in that it can spread more easily but not be as severe (I understand that it is unlikely nature requires a trade-off). I ask as my concern is that while this variant might be much more effective at spreading and hopefully less severe in its disease - are we not just making a massive breeding ground for the variant after this one that could potentially be as quick spreading but with a greater severity of disease?

gjsman-1000 5y ago
From what I know as not being a professional doctor, I would say that it appears to me that viruses get less dangerous over time, not more dangerous. This appears to be because viruses that are overly dangerous kill off their hosts too quickly, limiting their ability to spread, whereas the milder forms don't kill their hosts as easily and spread more broadly, building immunity against the stronger variants over time. Edit: The result of this, if you look at previous diseases that have plagued humanity (see Black Death), is a high initial death count when the virus breaks out, but the death rate declines as the milder variants spread and people survive them, building immunity to stronger versions, until eventually the virus mostly disappears.
- ceejayoz 5y ago
  It's not something you can count on; smallpox remained highly lethal across thousands of years. There's probably also a bit of an element of natural selection against humans involved; the people who died early of the Black Death may have been genetically more susceptible to it.
loup-vaillant 5y ago
I’ve heard that it depends on the virus. Some become less severe as they become more contagious, but sometimes their severity stays the same. Naively, you’d think selection pressure would decrease severity, because severity is not how viruses spread. However, if (some of) the same mechanisms that ar causing the virus to spread better are also responsible for (some of) its severity, then things may not really get better over time —unless our immune systems themselves adapt, but that generally requires a first infection…
moreira 5y ago
You are right about the trade-off: A more infectious, less deadly virus is the natural evolutionary path for them. But about the breeding ground, not really: If one day some super deadly variant evolves, it's not popping up in all of the infected hosts at the same time. It'd still need to infect everyone from scratch, and since we all have our guard up right now, it'd definitely have an incredibly hard time doing so.
mikepurvis 5y ago
"I am hoping that it would be some kind of trade off that the virus makes in that it can spread more easily but not be as severe..." I've definitely seen outlets postulating that the endgame for COVID-19 would be it doing exactly this— becoming way more contagious but way less severe, basically a just a kind of cold. These "final" variants would quickly spread everywhere, choking off the supply of new hosts for the more deadly variants, effectively achieving herd immunity.
coldcode 5y ago
Any genetic mutation which causes premature death of the host, or fails to be communicative will generally die off. Any mutation which keeps the host alive (or at least longer), or makes it easier to transmit the virus to another host, will keep the virus around. This type of behavior can be muted if there is an animal host that acts as a reservoir.
- not2b 5y ago
  Unfortunately, mink and white-tailed deer (the most common deer in the eastern US) are Covid reservoirs now. Probably other mammals as well.
- heavyset_go 5y ago
  > Any genetic mutation which causes premature death of the host, or fails to be communicative will generally die off. Any mutation which keeps the host alive (or at least longer), or makes it easier to transmit the virus to another host, will keep the virus around. Not necessarily[1]: > Some viruses provoke severe symptoms in their hosts that make it easier to transmit the virus to others. But those same symptoms can wind up killing the hosts. > Adalja said one example is Ebola, a deadly virus that spreads through the blood and body fluids of infected people. Another example is norovirus, which causes diarrhea and vomiting, and leads to hundreds of deaths each year in the U.S. > “The virus, speaking anthropomorphically, just wants to spread and have its genes replicated,” said Adalja. “If the best way for it is to spread by causing severe symptoms it will continue to do that.” [1] https://apnews.com/article/fact-checking-011488089270 https://apnews.com/article/fact-checking-011488089270
rich_sasha 5y ago
Sort of. Sometimes. Viruses evolve according to evolutionary pressures. I'm surprised we don't see Covid mutations that invalidate PCR tests - perhaps it's too soon, or even, who knows, maybe they are there and we don't know? The common trope is that if the virus is too deadly, then it doesn't have a chance to find new hosts. This is kind-of what happened to "SARS-1" - it tended to kill its hosts before they could pass it on. Unfortunately, this is only a weak effect in Covid. Most of the spread happens well before people are very ill; in terminal stages of severe Covid, many people in fact would test negative for virus presence. So there is little evolutionary pressure on the virus to be less deadly - by the time it kills people, we are spent vessels from its point of view. I suppose a mutation that makes it completely benign would be beneficial, as current rules on self-isolation curb the spread of strains causing symptomatic disease. There are pressures that make it more deadly: a mutation leading to higher viral load is both more deadly and more transmissible. So unless the transmissibility increases too much (and virus is way too deadly), we might even expect the virus to become more deadly. This hasn't happened yet, thankfully. An example I used elsewhere was the introduction of Myxomatosis in Australia, to control the invasive rabbit population. Over time, the local strain evolved to be more deadly, but with a longer incubation periods. This way, bunnies had more time to pass the virus around, then once that job was done, the virus was happy to kill them off. On the flipside (and very long timescales), since some people appear to be genetically more resistant to the virus, you can expect natural selection to do its job. But since overall death rate from Covid is low-ish (no more than 1%, you'd say, and skewed towards older, non-reproducing individuals) this would take a long time. Another hope is that, if the disease is less serious in children, perhaps immunity it built up during the usual period of childhood infections. There is another coronavirus, which causes a mild cold in children, but can be very serious in adults (apologies, I can't remember what it's called). Thankfully, a single infection gives more-or-less complete lifetime protection - so most people have it as children and never worry about it again. In either of these cases, we're talking about generational timescales.
- ufo 5y ago
  Apparently there are some variants of Omicron that can't be detected with current PCR tests. We may need to update the list of primers at some point. https://www.theguardian.com/world/2021/dec/07/scientists-find-stealth-version-of-omicron-not-identifiable-with-pcr-test-covid-variant https://www.theguardian.com/world/2021/dec/07/scientists-fin...
simonh 5y ago
gjsman addressed the issue of severity very well, so I'll just comment on tradeoffs. The adaptations that affect severity and those that affect transmissibility generally seem to be different. These are two axes on which a new variant can very in either way. The most successful new variants will tend to be highly transmissible (for obvious reasons) but also tend to be lower severity for the reasons gjsman gave in a sibling comment. That's only a tendency though, evolution will throw up variants on all sorts of different points on the transmissibility and severity scales and may the most successful virus win. Yes high severity variants will tend to kill off their victims sooner, but if also highly infectious that might overcome that effect. In any case killing off victims still leaves a trail of devastation. It can take a while for all of this to play out.
fer 5y ago
It depends on what you call severity. If severity means the host dies quickly rather than slowly, there's obviously selection pressure and that mutation will die off relatively quickly vs the rest, since it won't have as many chances to spread as the less severe strain. E.g. SARS/MERS. If severity means the host dies more often, but it still takes a long time to die, the selection pressure is much lower, and it will roughly spread the same as the less severe strain, all other things being the same. E.g. Spanish Flu.
- jjk166 5y ago
  Spanish Flu did evolve to become more mild. All modern seasonal flu variants are descended from it.
  - fer 5y ago
    Eventually. But as it appeared it was more virulent than its immediate ancestors.
    - jjk166 5y ago
      Eventually in this case being approximately 18-24 months from the first wave, which coincidentally is very close to where we are in the current pandemic.
      - bink 5y ago
        The Spanish Flu is a single data point. I wouldn't read too much into the 18-24 months stat.
        jjk166 5y ago
        The point isn't that Covid will be as fast as the Spanish Flu, it's that the Spanish Flu did not take a long time, and should not be dismissed as an example where it became milder eventually. In fact, we'd have to be quite lucky if covid became mild in the same time frame.
cableshaft 5y ago
One thing that makes Covid-19 a bit different from other viruses that have trended towards milder infections is its long incubation time (while still being infectious). So it can already spread pretty easily even if it's killing those people, and thus there's not a lot of darwinian pressure to become milder. It might still trend towards that over time, but it will probably be slower at it than other viruses, and thus the 'it gets milder over time' aphorism about viruses doesn't apply as strongly to Covid-19.
- zamfi 5y ago
  That’s only one pressure driving viral evolution. Another pressure is social response to infection: so far, the predominant response to a more-virulent or more-lethal strain has been lockdown and/or other behavioral change, see: delta in India. On the flip side, a variant that causes milder symptoms is less likely to cause the same social response, which allows the virus to spread more widely. This may (may!) be what we’re observing with Omicron. In any case, we’ll know much more in a few weeks.
  - cableshaft 5y ago
    I'd say that's normally true, but there's not a ton of lockdowns with even Delta right now, so while I agree that it probably isn't going to get worse, there's still not a ton of pressure from social response as it is right now for it to get milder (maybe you could argue pressure from vaccines I guess).
    - daxfohl 5y ago
      Yeah I think we can learn what society thinks is acceptable risk just by looking at death counts over the last two years. They've pretty much leveled out. So as the virus mutates into less (or more) harmful variations, we'll see the world react less (or more) strictly, but overall death count will remain stable.
      - daxfohl 5y ago
        Presumably the steady state will happen after the virus mutates into a less dangerous variant (as infecting more people will be evolutionarily advantageous for the virus), and eventually we all get it and build up antibodies, at which point its virulence further subsides.
clashmoore 5y ago
I can't find the excerpt, but I read "The Great Influenza: The Story of the Deadliest Pandemic in History" by John M. Barry during this pandemic. It was an okay read if you're looking for something to pass the time. There was a passage that suggested that virus evolutions happens all the time which sometimes gives us a super severe strain. But usually these super sever strains don't evolve into even more severe strains - generally they evolve back towards the "baseline" severity and the severe strain burns itself out. From that, I had hope that the Delta variant of COVID was one of these outlier super severe strains and that all subsequent evolutions would fall back but it's not looking like that is the case when omicron was found.
julianozen 5y ago
I am not a professional. I have been basing a lot of my virus information from Tomas Pueyo. Here is my source: https://unchartedterritories.tomaspueyo.com/p/the-omicron-question https://unchartedterritories.tomaspueyo.com/p/the-omicron-qu... In this article he clarified that generally viruses that spread more are less severe (as killing the host makes it tougher to spread). The asymptotic nature of Covid sort of broke this assumption because Covid can lie dormant in someone for a week before the person shows severe illness
- QuarterReptile 5y ago
  >In this article he clarified that generally viruses that spread more are less severe (as killing the host makes it tougher to spread). It takes far less than death to reduce spread. People who feel sick stay home from work (not guaranteed, but with enough frequency that it matters), don't go out to eat, don't wander around and go to parties, and so on. Any time they're sitting home, they've hurt the chances that their variant is the winning-est variant. Again with the caveat about dormancy periods for Covid.
- sjwalter 5y ago
  Asymptomatic spread is not nearly as prevalent as originally feared. Also, those who do not get symptoms (that is, most who catch covid) do not spread the virus in general, which is why it's now called "presymptomatic" spread.
- Heliosmaster 5y ago
  Yeah, technically a variant who lies dormant for a long time while spreading slowly is a better fit than one that is noticed. Didn't we learn anything from Plague Inc?
wayfarer1291 5y ago
Not necessarily. Smallpox was around for a very long time till we vaccinated our way out of it. Same with polio.
Fiahil 5y ago
Play with Plague Inc. (https://www.ndemiccreations.com/en/22-plague-inc https://www.ndemiccreations.com/en/22-plague-inc) Every single press title the last two years can be related somehow to a single Game. New variants, new mutations, spreading faster vs killing more people, ... All these tradeoffs are quite well modeled. Building a resistance to vaccines ("the cure") is also one areas where your virus can evolve, and -to be honnest- I prefer it to fight vaccines than to develop a "total organ failure" mutation.
- dtech 5y ago
  It's a game, not a model. Real mutations aren't directed or instantly spread to all infected people like in the game. Iirc people also don't get better once infected.
shtopointo 5y ago
Not an expert, but from hearing about it from various sources: As viruses evolve they generally have 2 paths of evolution – they either become more deadly, or more contagious. The ones that become more deadly will kill the host quicker, and so won't have enough time to spread to others. The ones that become more contagious are by definition weaker, they will spread to more people, but the effects will be milder. There are some theories to suggest that pandemics (like the Spanish flu) ended because the virus eventually mutated to a milder, more contagious form.
deleted 5y ago
[deleted]
cblconfederate 5y ago
Viruses evolve to be more fit. Presumably, a mild version and more contagious version may even have evolved in one of the billions that were infected these years, but it didn't spread much because of self-isolation and restrictions. A variand that s more debilitating would be less likely to transmit.
alliao 5y ago
I once hoped a lesser severe but a more transmissible variant would win, but then I don't think HIV did or at least within my life time.
gilbetron 5y ago
No one replying has a "serious level of knowledge", so instead, turn to sources that do (or report serious sources!) https://www.smithsonianmag.com/science-nature/how-viruses-evolve-180975343/ https://www.smithsonianmag.com/science-nature/how-viruses-ev... https://pubmed.ncbi.nlm.nih.gov/30734920/ https://pubmed.ncbi.nlm.nih.gov/30734920/ (really good one) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7255208/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7255208/ In short, we don't know and won't know until this is all "over" a few years in the future, at least.
- joebob42 5y ago
  Imo part of the joy of hn is that this isn't actually true. Obviously not everyone knows what they are talking about, but some of the people who really do have serious knowledge on any given topic are on hn, and the average person here is at least slightly less likely to think they have knowledge when in fact they don't.
  - mensetmanusman 5y ago
    Yeah I remember in June of 2020 discussing the new aerosol data on HN and cringing about the 6 ft recommendation with cloth masks indoors. Finally a year+ later the WHO admitted as such (aerosol risk can be >50 ft for hours after a spread event), so sometimes we are ahead :)
    - clairity 5y ago
      > "aerosol risk can be >50 ft for hours after a spread event" no, that's cringeworthy fearmongering. the virus is fragile and falls apart relatively quickly outside the body. the main risk behavior is having long conversations in close quarters where you're constantly exposed to a warm airstream of live virus.
      - mensetmanusman 5y ago
        In the right humidity conditions with poor airflow it has been found to be stable for hours, this is how there were super spreader events from 1>500 in certain types of factories.
deleted 5y ago
[deleted]

gjsman-1000 5y ago

From what I know as not being a professional doctor, I would say that it appears to me that viruses get less dangerous over time, not more dangerous. This appears to be because viruses that are overly dangerous kill off their hosts too quickly, limiting their ability to spread, whereas the milder forms don't kill their hosts as easily and spread more broadly, building immunity against the stronger variants over time. Edit: The result of this, if you look at previous diseases that have plagued humanity (see Black Death), is a high initial death count when the virus breaks out, but the death rate declines as the milder variants spread and people survive them, building immunity to stronger versions, until eventually the virus mostly disappears.

ceejayoz 5y ago
It's not something you can count on; smallpox remained highly lethal across thousands of years. There's probably also a bit of an element of natural selection against humans involved; the people who died early of the Black Death may have been genetically more susceptible to it.

loup-vaillant 5y ago

I’ve heard that it depends on the virus. Some become less severe as they become more contagious, but sometimes their severity stays the same. Naively, you’d think selection pressure would decrease severity, because severity is not how viruses spread. However, if (some of) the same mechanisms that ar causing the virus to spread better are also responsible for (some of) its severity, then things may not really get better over time —unless our immune systems themselves adapt, but that generally requires a first infection…

moreira 5y ago

You are right about the trade-off: A more infectious, less deadly virus is the natural evolutionary path for them. But about the breeding ground, not really: If one day some super deadly variant evolves, it's not popping up in all of the infected hosts at the same time. It'd still need to infect everyone from scratch, and since we all have our guard up right now, it'd definitely have an incredibly hard time doing so.

mikepurvis 5y ago

"I am hoping that it would be some kind of trade off that the virus makes in that it can spread more easily but not be as severe..." I've definitely seen outlets postulating that the endgame for COVID-19 would be it doing exactly this— becoming way more contagious but way less severe, basically a just a kind of cold. These "final" variants would quickly spread everywhere, choking off the supply of new hosts for the more deadly variants, effectively achieving herd immunity.

coldcode 5y ago

Any genetic mutation which causes premature death of the host, or fails to be communicative will generally die off. Any mutation which keeps the host alive (or at least longer), or makes it easier to transmit the virus to another host, will keep the virus around. This type of behavior can be muted if there is an animal host that acts as a reservoir.

not2b 5y ago
Unfortunately, mink and white-tailed deer (the most common deer in the eastern US) are Covid reservoirs now. Probably other mammals as well.
heavyset_go 5y ago
> Any genetic mutation which causes premature death of the host, or fails to be communicative will generally die off. Any mutation which keeps the host alive (or at least longer), or makes it easier to transmit the virus to another host, will keep the virus around. Not necessarily[1]: > Some viruses provoke severe symptoms in their hosts that make it easier to transmit the virus to others. But those same symptoms can wind up killing the hosts. > Adalja said one example is Ebola, a deadly virus that spreads through the blood and body fluids of infected people. Another example is norovirus, which causes diarrhea and vomiting, and leads to hundreds of deaths each year in the U.S. > “The virus, speaking anthropomorphically, just wants to spread and have its genes replicated,” said Adalja. “If the best way for it is to spread by causing severe symptoms it will continue to do that.” [1] https://apnews.com/article/fact-checking-011488089270 https://apnews.com/article/fact-checking-011488089270

rich_sasha 5y ago

Sort of. Sometimes. Viruses evolve according to evolutionary pressures. I'm surprised we don't see Covid mutations that invalidate PCR tests - perhaps it's too soon, or even, who knows, maybe they are there and we don't know? The common trope is that if the virus is too deadly, then it doesn't have a chance to find new hosts. This is kind-of what happened to "SARS-1" - it tended to kill its hosts before they could pass it on. Unfortunately, this is only a weak effect in Covid. Most of the spread happens well before people are very ill; in terminal stages of severe Covid, many people in fact would test negative for virus presence. So there is little evolutionary pressure on the virus to be less deadly - by the time it kills people, we are spent vessels from its point of view. I suppose a mutation that makes it completely benign would be beneficial, as current rules on self-isolation curb the spread of strains causing symptomatic disease. There are pressures that make it more deadly: a mutation leading to higher viral load is both more deadly and more transmissible. So unless the transmissibility increases too much (and virus is way too deadly), we might even expect the virus to become more deadly. This hasn't happened yet, thankfully. An example I used elsewhere was the introduction of Myxomatosis in Australia, to control the invasive rabbit population. Over time, the local strain evolved to be more deadly, but with a longer incubation periods. This way, bunnies had more time to pass the virus around, then once that job was done, the virus was happy to kill them off. On the flipside (and very long timescales), since some people appear to be genetically more resistant to the virus, you can expect natural selection to do its job. But since overall death rate from Covid is low-ish (no more than 1%, you'd say, and skewed towards older, non-reproducing individuals) this would take a long time. Another hope is that, if the disease is less serious in children, perhaps immunity it built up during the usual period of childhood infections. There is another coronavirus, which causes a mild cold in children, but can be very serious in adults (apologies, I can't remember what it's called). Thankfully, a single infection gives more-or-less complete lifetime protection - so most people have it as children and never worry about it again. In either of these cases, we're talking about generational timescales.

ufo 5y ago
Apparently there are some variants of Omicron that can't be detected with current PCR tests. We may need to update the list of primers at some point. https://www.theguardian.com/world/2021/dec/07/scientists-find-stealth-version-of-omicron-not-identifiable-with-pcr-test-covid-variant https://www.theguardian.com/world/2021/dec/07/scientists-fin...

simonh 5y ago

gjsman addressed the issue of severity very well, so I'll just comment on tradeoffs. The adaptations that affect severity and those that affect transmissibility generally seem to be different. These are two axes on which a new variant can very in either way. The most successful new variants will tend to be highly transmissible (for obvious reasons) but also tend to be lower severity for the reasons gjsman gave in a sibling comment. That's only a tendency though, evolution will throw up variants on all sorts of different points on the transmissibility and severity scales and may the most successful virus win. Yes high severity variants will tend to kill off their victims sooner, but if also highly infectious that might overcome that effect. In any case killing off victims still leaves a trail of devastation. It can take a while for all of this to play out.

fer 5y ago

It depends on what you call severity. If severity means the host dies quickly rather than slowly, there's obviously selection pressure and that mutation will die off relatively quickly vs the rest, since it won't have as many chances to spread as the less severe strain. E.g. SARS/MERS. If severity means the host dies more often, but it still takes a long time to die, the selection pressure is much lower, and it will roughly spread the same as the less severe strain, all other things being the same. E.g. Spanish Flu.

jjk166 5y ago
Spanish Flu did evolve to become more mild. All modern seasonal flu variants are descended from it.
- fer 5y ago
  Eventually. But as it appeared it was more virulent than its immediate ancestors.
  - jjk166 5y ago
    Eventually in this case being approximately 18-24 months from the first wave, which coincidentally is very close to where we are in the current pandemic.
    - bink 5y ago
      The Spanish Flu is a single data point. I wouldn't read too much into the 18-24 months stat.
      - jjk166 5y ago
        The point isn't that Covid will be as fast as the Spanish Flu, it's that the Spanish Flu did not take a long time, and should not be dismissed as an example where it became milder eventually. In fact, we'd have to be quite lucky if covid became mild in the same time frame.

cableshaft 5y ago

One thing that makes Covid-19 a bit different from other viruses that have trended towards milder infections is its long incubation time (while still being infectious). So it can already spread pretty easily even if it's killing those people, and thus there's not a lot of darwinian pressure to become milder. It might still trend towards that over time, but it will probably be slower at it than other viruses, and thus the 'it gets milder over time' aphorism about viruses doesn't apply as strongly to Covid-19.

zamfi 5y ago
That’s only one pressure driving viral evolution. Another pressure is social response to infection: so far, the predominant response to a more-virulent or more-lethal strain has been lockdown and/or other behavioral change, see: delta in India. On the flip side, a variant that causes milder symptoms is less likely to cause the same social response, which allows the virus to spread more widely. This may (may!) be what we’re observing with Omicron. In any case, we’ll know much more in a few weeks.
- cableshaft 5y ago
  I'd say that's normally true, but there's not a ton of lockdowns with even Delta right now, so while I agree that it probably isn't going to get worse, there's still not a ton of pressure from social response as it is right now for it to get milder (maybe you could argue pressure from vaccines I guess).
  - daxfohl 5y ago
    Yeah I think we can learn what society thinks is acceptable risk just by looking at death counts over the last two years. They've pretty much leveled out. So as the virus mutates into less (or more) harmful variations, we'll see the world react less (or more) strictly, but overall death count will remain stable.
    - daxfohl 5y ago
      Presumably the steady state will happen after the virus mutates into a less dangerous variant (as infecting more people will be evolutionarily advantageous for the virus), and eventually we all get it and build up antibodies, at which point its virulence further subsides.

clashmoore 5y ago

I can't find the excerpt, but I read "The Great Influenza: The Story of the Deadliest Pandemic in History" by John M. Barry during this pandemic. It was an okay read if you're looking for something to pass the time. There was a passage that suggested that virus evolutions happens all the time which sometimes gives us a super severe strain. But usually these super sever strains don't evolve into even more severe strains - generally they evolve back towards the "baseline" severity and the severe strain burns itself out. From that, I had hope that the Delta variant of COVID was one of these outlier super severe strains and that all subsequent evolutions would fall back but it's not looking like that is the case when omicron was found.

julianozen 5y ago

I am not a professional. I have been basing a lot of my virus information from Tomas Pueyo. Here is my source: https://unchartedterritories.tomaspueyo.com/p/the-omicron-question https://unchartedterritories.tomaspueyo.com/p/the-omicron-qu... In this article he clarified that generally viruses that spread more are less severe (as killing the host makes it tougher to spread). The asymptotic nature of Covid sort of broke this assumption because Covid can lie dormant in someone for a week before the person shows severe illness

QuarterReptile 5y ago
>In this article he clarified that generally viruses that spread more are less severe (as killing the host makes it tougher to spread). It takes far less than death to reduce spread. People who feel sick stay home from work (not guaranteed, but with enough frequency that it matters), don't go out to eat, don't wander around and go to parties, and so on. Any time they're sitting home, they've hurt the chances that their variant is the winning-est variant. Again with the caveat about dormancy periods for Covid.
sjwalter 5y ago
Asymptomatic spread is not nearly as prevalent as originally feared. Also, those who do not get symptoms (that is, most who catch covid) do not spread the virus in general, which is why it's now called "presymptomatic" spread.
Heliosmaster 5y ago
Yeah, technically a variant who lies dormant for a long time while spreading slowly is a better fit than one that is noticed. Didn't we learn anything from Plague Inc?

wayfarer1291 5y ago

Not necessarily. Smallpox was around for a very long time till we vaccinated our way out of it. Same with polio.

Fiahil 5y ago

Play with Plague Inc. (https://www.ndemiccreations.com/en/22-plague-inc https://www.ndemiccreations.com/en/22-plague-inc) Every single press title the last two years can be related somehow to a single Game. New variants, new mutations, spreading faster vs killing more people, ... All these tradeoffs are quite well modeled. Building a resistance to vaccines ("the cure") is also one areas where your virus can evolve, and -to be honnest- I prefer it to fight vaccines than to develop a "total organ failure" mutation.

dtech 5y ago
It's a game, not a model. Real mutations aren't directed or instantly spread to all infected people like in the game. Iirc people also don't get better once infected.

shtopointo 5y ago

Not an expert, but from hearing about it from various sources: As viruses evolve they generally have 2 paths of evolution – they either become more deadly, or more contagious. The ones that become more deadly will kill the host quicker, and so won't have enough time to spread to others. The ones that become more contagious are by definition weaker, they will spread to more people, but the effects will be milder. There are some theories to suggest that pandemics (like the Spanish flu) ended because the virus eventually mutated to a milder, more contagious form.

deleted 5y ago

[deleted]

cblconfederate 5y ago

Viruses evolve to be more fit. Presumably, a mild version and more contagious version may even have evolved in one of the billions that were infected these years, but it didn't spread much because of self-isolation and restrictions. A variand that s more debilitating would be less likely to transmit.

alliao 5y ago

I once hoped a lesser severe but a more transmissible variant would win, but then I don't think HIV did or at least within my life time.

gilbetron 5y ago

No one replying has a "serious level of knowledge", so instead, turn to sources that do (or report serious sources!) https://www.smithsonianmag.com/science-nature/how-viruses-evolve-180975343/ https://www.smithsonianmag.com/science-nature/how-viruses-ev... https://pubmed.ncbi.nlm.nih.gov/30734920/ https://pubmed.ncbi.nlm.nih.gov/30734920/ (really good one) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7255208/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7255208/ In short, we don't know and won't know until this is all "over" a few years in the future, at least.

joebob42 5y ago
Imo part of the joy of hn is that this isn't actually true. Obviously not everyone knows what they are talking about, but some of the people who really do have serious knowledge on any given topic are on hn, and the average person here is at least slightly less likely to think they have knowledge when in fact they don't.
- mensetmanusman 5y ago
  Yeah I remember in June of 2020 discussing the new aerosol data on HN and cringing about the 6 ft recommendation with cloth masks indoors. Finally a year+ later the WHO admitted as such (aerosol risk can be >50 ft for hours after a spread event), so sometimes we are ahead :)
  - clairity 5y ago
    > "aerosol risk can be >50 ft for hours after a spread event" no, that's cringeworthy fearmongering. the virus is fragile and falls apart relatively quickly outside the body. the main risk behavior is having long conversations in close quarters where you're constantly exposed to a warm airstream of live virus.
    - mensetmanusman 5y ago
      In the right humidity conditions with poor airflow it has been found to be stable for hours, this is how there were super spreader events from 1>500 in certain types of factories.

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