5 ms·

There is a lot to unpack but I doubt you are as right as you think you are. For instance in new variant outbreaks there ate usually harsher responses than for k

There is a lot to unpack but I doubt you are as right as you think you are. For instance in new variant outbreaks there ate usually harsher responses than for known variant outbreaks, so it is very difficult to identity the real infectivity. But more importantly it's well established that diseases that those diseases spread most widely that don't kill rapidly (or that more generally don't have severe symptoms) and that have a longer period between the start of infectivity (= shortly after infection) and the onset of identifiable symptoms. So you would indeed anticipate that any disease that runs sufficiently long in the population becomes more mild and has a later onset of symptoms as variants with these features outcompete thr others. In other words: it is expected that covid mutates over time to become more mild on average. But that doesn't mean that everyone survives. Infection rates in many countries are higher than ever, which even if the % of severe cases is lower than with other variants, delta and omicron will still kill and have severe long-term effects on many.

oneoff786 5y ago
I can’t tell what your point is but nothing here seems to contradict anything I said. It’s just some facts about diseases. I didn’t say every one was going to survive omicron. I said the spread was unlikely to be materially higher than its predecessor and likely have a lower negative impact. A disease that spreads twice as fast is unlikely to infect twice as many people (over the long term). A disease that causes fewer adverse effects, let’s say half as often, needs to, by definition, infect twice as many people over the long run in order to cause the same amount of harm. As a dumb mental model, if omicron is 30% less dangerous, then omicron needs to infect 42% more people to be as harmful to society. That is very difficult to achieve, especially given our collective immunity achieved so far. I would say there is little chance of this occurring.
- zuminator 5y ago
  Is anyone even seriously claiming that a disease that spreads twice as fast is going to infect twice as many people? As long as the effective R0 of a disease remains greater than 1, it's eventually going to infect the same amount of people — everyone (over the long term). Greater R0 rate just means it spreads faster. The real concerns about omicron are that: 1) A rapid initial spread will overwhelm the healthcare system and 2) that if its basic R0 rate is sufficiently high, then even after remedial measures are taken, we will still be left with an effective R0 rate above 1 for quite some time.
  - sudosysgen 5y ago
    That's not how it works. Diseases dont infect everyone. Assuming no reinfection, at R0 of 1.3 a disease will only infect around 30% of the population.
    - zuminator 5y ago
      If I conveyed the impression that I thought the effective R0 could remain above 1 indefinitely, that is my error. But why assume no reinfection, that's not what we're seeing so far with SARS-CoV-2.
      - sudosysgen 5y ago
        That is not quite what R0 means. R0 is the reproductive rate in a naive population. I believe the variable you are looking for is R(t), which is the effective reproductive rate at any point of time.
        zuminator 5y ago
        Thank you. I've seen the phrase "effective R0" used, for example, here [0], but I can see that you are correct that R(t) is the generally accepted epidemiological term. [0] https://labblog.uofmhealth.org/rounds/how-scientists-quantify-intensity-of-an-outbreak-like-covid-19 https://labblog.uofmhealth.org/rounds/how-scientists-quantif...
        clairity 5y ago
        this is a mathematical convention, not simply an epidemiological term. the 0th term of any function, like R0, is generally understood as the initial condition constant (at time t=0). R(t) is a function of time and R0 is the value of R at time 0, the initial condition. R0 tells you exactly nothing about the future, it only pins down the starting point (which is important information, but not the be-all-and-end-all of it). i’ve been mildly amused/dismayed by the constant misplaced focus on R0 over the past 2 years by the media/laypeople, given this essential context.
pg314 5y ago
Covid-19 doesn't kill rapidly, so there is no pressure for it to mutate to become milder.
- deleted 5y ago
  [deleted]
- mekkkkkk 5y ago
  The milder it gets, the less noticeable it is. As it gets less noticeable, the chance of exposure to new hosts increases. Seems reasonable.
  - senectus1 5y ago
    the real question is, can we pivot faster than evolution can...
  - heavyset_go 5y ago
    The milder it gets, the less it is able to spread because disease symptoms are what help spread the disease in the first place. Also, there are selection pressures that select for increased virulence, otherwise all viruses would have evolved to be completely benign billions of years ago.
    - mekkkkkk 5y ago
      That makes a lot of sense too! I guess the sweet spot is where you'd find the persistent seasonal flues. Mild enough for people to be reckless, but virulent enough to cause sufficient spread.
- 7952 5y ago
  I think the effect is the same once the patient is quarantined. If they survive two days or two weeks the virus is unable to spread either way.
- bewaretheirs 5y ago
  There's also no evolutionary pressure to conserve its lethality. What appears to have happened with Omicron is that it has mutated in a way that increases transmission at the expense of lethality: https://www.med.hku.hk/en/news/press/20211215-omicron-sars-cov-2-infection https://www.med.hku.hk/en/news/press/20211215-omicron-sars-c...
heavyset_go 5y ago
COVID isn't particularly deadly. The selection pressure that can cause a virus to become weaker is mediated by the virus dying off in the corpses it creates. People aren't dropping like flies from COVID, so that selection pressure isn't there, and the virus is free to mutate into more virulent forms. There's no reason to expect a relatively mild, yet still deadly, virus to become weaker, especially if our medical infrastructure keeps people alive that would've otherwise died from infection. Virus evolution tends to optimize for replication and transmission, and not reduced severity. If a particular mutation causes a virus to replicate better than other variants, but it ends up killing hosts more often, it doesn't really matter what happens to the host afterwards, evoluntionarily, as the virus has already spread it genes more than it did before it mutated.
- dontcare007 5y ago

oneoff786 5y ago

I can’t tell what your point is but nothing here seems to contradict anything I said. It’s just some facts about diseases. I didn’t say every one was going to survive omicron. I said the spread was unlikely to be materially higher than its predecessor and likely have a lower negative impact. A disease that spreads twice as fast is unlikely to infect twice as many people (over the long term). A disease that causes fewer adverse effects, let’s say half as often, needs to, by definition, infect twice as many people over the long run in order to cause the same amount of harm. As a dumb mental model, if omicron is 30% less dangerous, then omicron needs to infect 42% more people to be as harmful to society. That is very difficult to achieve, especially given our collective immunity achieved so far. I would say there is little chance of this occurring.

zuminator 5y ago
Is anyone even seriously claiming that a disease that spreads twice as fast is going to infect twice as many people? As long as the effective R0 of a disease remains greater than 1, it's eventually going to infect the same amount of people — everyone (over the long term). Greater R0 rate just means it spreads faster. The real concerns about omicron are that: 1) A rapid initial spread will overwhelm the healthcare system and 2) that if its basic R0 rate is sufficiently high, then even after remedial measures are taken, we will still be left with an effective R0 rate above 1 for quite some time.
- sudosysgen 5y ago
  That's not how it works. Diseases dont infect everyone. Assuming no reinfection, at R0 of 1.3 a disease will only infect around 30% of the population.
  - zuminator 5y ago
    If I conveyed the impression that I thought the effective R0 could remain above 1 indefinitely, that is my error. But why assume no reinfection, that's not what we're seeing so far with SARS-CoV-2.
    - sudosysgen 5y ago
      That is not quite what R0 means. R0 is the reproductive rate in a naive population. I believe the variable you are looking for is R(t), which is the effective reproductive rate at any point of time.
      - zuminator 5y ago
        Thank you. I've seen the phrase "effective R0" used, for example, here [0], but I can see that you are correct that R(t) is the generally accepted epidemiological term. [0] https://labblog.uofmhealth.org/rounds/how-scientists-quantify-intensity-of-an-outbreak-like-covid-19 https://labblog.uofmhealth.org/rounds/how-scientists-quantif...
        clairity 5y ago
        this is a mathematical convention, not simply an epidemiological term. the 0th term of any function, like R0, is generally understood as the initial condition constant (at time t=0). R(t) is a function of time and R0 is the value of R at time 0, the initial condition. R0 tells you exactly nothing about the future, it only pins down the starting point (which is important information, but not the be-all-and-end-all of it). i’ve been mildly amused/dismayed by the constant misplaced focus on R0 over the past 2 years by the media/laypeople, given this essential context.

pg314 5y ago

Covid-19 doesn't kill rapidly, so there is no pressure for it to mutate to become milder.

deleted 5y ago
[deleted]
mekkkkkk 5y ago
The milder it gets, the less noticeable it is. As it gets less noticeable, the chance of exposure to new hosts increases. Seems reasonable.
- senectus1 5y ago
  the real question is, can we pivot faster than evolution can...
- heavyset_go 5y ago
  The milder it gets, the less it is able to spread because disease symptoms are what help spread the disease in the first place. Also, there are selection pressures that select for increased virulence, otherwise all viruses would have evolved to be completely benign billions of years ago.
  - mekkkkkk 5y ago
    That makes a lot of sense too! I guess the sweet spot is where you'd find the persistent seasonal flues. Mild enough for people to be reckless, but virulent enough to cause sufficient spread.
7952 5y ago
I think the effect is the same once the patient is quarantined. If they survive two days or two weeks the virus is unable to spread either way.
bewaretheirs 5y ago
There's also no evolutionary pressure to conserve its lethality. What appears to have happened with Omicron is that it has mutated in a way that increases transmission at the expense of lethality: https://www.med.hku.hk/en/news/press/20211215-omicron-sars-cov-2-infection https://www.med.hku.hk/en/news/press/20211215-omicron-sars-c...

heavyset_go 5y ago

COVID isn't particularly deadly. The selection pressure that can cause a virus to become weaker is mediated by the virus dying off in the corpses it creates. People aren't dropping like flies from COVID, so that selection pressure isn't there, and the virus is free to mutate into more virulent forms. There's no reason to expect a relatively mild, yet still deadly, virus to become weaker, especially if our medical infrastructure keeps people alive that would've otherwise died from infection. Virus evolution tends to optimize for replication and transmission, and not reduced severity. If a particular mutation causes a virus to replicate better than other variants, but it ends up killing hosts more often, it doesn't really matter what happens to the host afterwards, evoluntionarily, as the virus has already spread it genes more than it did before it mutated.

dontcare007 5y ago