5 ms·

Measles is estimated to be about 300% more infectious than the delta variant, so if it surpassed measles it would be the most contagious viral disease known to

Measles is estimated to be about 300% more infectious than the delta variant, so if it surpassed measles it would be the most contagious viral disease known to man. It's already pretty close to what is assumed to be the "ceiling".

tehjoker 5y ago
300% is still a lot of room to grow. Delta is only about twice as bad as the wild type strain.
- marricks 5y ago
  I'm not sure "only twice as bad" paints an accurate picture. - Herd immunity is much harder. Calculated as 1 - 1/r0 where r0 is defined in relation to transmissibility. So if r0 = 3 that's ~66% need to be immune to stop the virus. If r0 = 6 that's 83% needed, much higher threshold. - The virus is only getting more deadly. A preprint study found delta has "120% greater risk of hospitalization, 287% greater risk of ICU admission and 137% greater risk of death"[1] Also 225% more transmissible is 3x more unless I'm doing my math wrong?[2] [1] https://en.wikipedia.org/wiki/SARS-CoV-2_Delta_variant#Virulence https://en.wikipedia.org/wiki/SARS-CoV-2_Delta_variant#Virul... [2] https://en.wikipedia.org/wiki/SARS-CoV-2_Delta_variant#Transmissibility https://en.wikipedia.org/wiki/SARS-CoV-2_Delta_variant#Trans...
  - nradov 5y ago
    Right which is why achieving any meaningful level of herd immunity is now effectively impossible. Thus we're all likely to get infected eventually. https://www.businessinsider.com/delta-variant-made-herd-immunity-not-possible-astrazeneca-developer-2021-8 https://www.businessinsider.com/delta-variant-made-herd-immu... Fortunately the vaccines are very effective at preventing death for all variants.
    - Retric 5y ago
      Herd immunity happens long before we are all infected. Less than 40% of the US population is completely unvaccinated, which means we can open up more without overwhelming hospitals. That does put the unvaccinated at increased risks, but the general public is seemingly unwilling to continue lockdowns to protect people choosing not to be vaccinated. If ~85% is needed for herd immunity then we could be rapidly approaching that point. Though specific locations would likely have outbreaks even if it was less of a concern nationally.
      - chinathrow 5y ago
        > Less than 40% of the US population is completely unvaccinated, which means we can open up more without overwhelming hospitals. Not sure where you get this about open up, but have you seen current ICU fill levels in various US states such as Alabamba etc?
        Retric 5y ago
        That’s quite regional. Nationwide there is still plenty of ICU beds available, and presumably if it gets bad enough hot spots will respond appropriately.
        chinathrow 5y ago
        Huh? If you have a heart attack or a stroke or a grave accident you need a regional ER asap, not one 5h away.
        Retric 5y ago
        By moving people with covid to other states, or importing medical personnel and equipment. Do so aggressively enough and you can keep capacity available.
        chinathrow 5y ago
        And then you'll eventually realize: having thousands of people getting intensive care at the same time until everyone either had it or died from it is moraly not acceptable. Why do you come up with the idea that it's better to increase capacity rather than using large scale vaccination efforts?
    - Sohcahtoa82 5y ago
      All likely to be infected, I certainly believe. But I've been operating under the assumption that while vaccination won't prevent you from infection, it is still highly effective (90%+) at reducing symptoms, even with Delta. I'm certainly open to learning if this is false, however. I've just seen statistics that over 95% of people hospitalized are unvaccinated.
      - kansface 5y ago
        I believe that number is in the 80s for the mRNA vaccines and lower for the others (minus the one from Russia).
        tunesmith 5y ago
        There are many efficacy numbers. mRNA does help against infection but efficacy is apparently low, like 50-60%. Makes sense because they weren't really developed with that in mind. Efficacy goes to 60-80% for symptomatic, over 80% for serious/hospitalization, and mid 90% for death. I think.
    - tunesmith 5y ago
      Right, and that's where vaccine efficacy comes into play. If r0 is 6 and HIT is 83.3%, but efficacy is only 90%, then you actually need about 93% vaccinated. And for herd immunity, what matters is transmission, and the vaccine efficacies for asymptomatic infection are pretty low; 50-60%. So mathematically impossible without severe lockdowns and/or improved vaccines that are better at preventing transmission.
  - polynomial 5y ago
    Do we have generally accepted R0 values for each of these 3 variants?
    - marricks 5y ago
      I think there's am R0 for initial strain and then ranges for the other variants. I thought it was in Wikipedia but either it's been edited out or I saw it elsewhere. What I recall (so huge grain of salt here) was R0 at 2.3 for initial strain then around 2x for Alpha and another 2-3x for Delta. Not. Great.
- tehjoker 5y ago
  Looking at the measles wikipedia article: "Furthermore, measles's reproductive number estimates vary beyond the frequently cited range of 12 to 18.[15] The NIH quote this 2017 paper saying: "[a] review in 2017 identified feasible measles R0 values of 3.7–203.3" https://en.wikipedia.org/wiki/Measles https://en.wikipedia.org/wiki/Measles

tehjoker 5y ago

300% is still a lot of room to grow. Delta is only about twice as bad as the wild type strain.

marricks 5y ago
I'm not sure "only twice as bad" paints an accurate picture. - Herd immunity is much harder. Calculated as 1 - 1/r0 where r0 is defined in relation to transmissibility. So if r0 = 3 that's ~66% need to be immune to stop the virus. If r0 = 6 that's 83% needed, much higher threshold. - The virus is only getting more deadly. A preprint study found delta has "120% greater risk of hospitalization, 287% greater risk of ICU admission and 137% greater risk of death"[1] Also 225% more transmissible is 3x more unless I'm doing my math wrong?[2] [1] https://en.wikipedia.org/wiki/SARS-CoV-2_Delta_variant#Virulence https://en.wikipedia.org/wiki/SARS-CoV-2_Delta_variant#Virul... [2] https://en.wikipedia.org/wiki/SARS-CoV-2_Delta_variant#Transmissibility https://en.wikipedia.org/wiki/SARS-CoV-2_Delta_variant#Trans...
- nradov 5y ago
  Right which is why achieving any meaningful level of herd immunity is now effectively impossible. Thus we're all likely to get infected eventually. https://www.businessinsider.com/delta-variant-made-herd-immunity-not-possible-astrazeneca-developer-2021-8 https://www.businessinsider.com/delta-variant-made-herd-immu... Fortunately the vaccines are very effective at preventing death for all variants.
  - Retric 5y ago
    Herd immunity happens long before we are all infected. Less than 40% of the US population is completely unvaccinated, which means we can open up more without overwhelming hospitals. That does put the unvaccinated at increased risks, but the general public is seemingly unwilling to continue lockdowns to protect people choosing not to be vaccinated. If ~85% is needed for herd immunity then we could be rapidly approaching that point. Though specific locations would likely have outbreaks even if it was less of a concern nationally.
    - chinathrow 5y ago
      > Less than 40% of the US population is completely unvaccinated, which means we can open up more without overwhelming hospitals. Not sure where you get this about open up, but have you seen current ICU fill levels in various US states such as Alabamba etc?
      - Retric 5y ago
        That’s quite regional. Nationwide there is still plenty of ICU beds available, and presumably if it gets bad enough hot spots will respond appropriately.
        chinathrow 5y ago
        Huh? If you have a heart attack or a stroke or a grave accident you need a regional ER asap, not one 5h away.
        Retric 5y ago
        By moving people with covid to other states, or importing medical personnel and equipment. Do so aggressively enough and you can keep capacity available.
        chinathrow 5y ago
        And then you'll eventually realize: having thousands of people getting intensive care at the same time until everyone either had it or died from it is moraly not acceptable. Why do you come up with the idea that it's better to increase capacity rather than using large scale vaccination efforts?
  - Sohcahtoa82 5y ago
    All likely to be infected, I certainly believe. But I've been operating under the assumption that while vaccination won't prevent you from infection, it is still highly effective (90%+) at reducing symptoms, even with Delta. I'm certainly open to learning if this is false, however. I've just seen statistics that over 95% of people hospitalized are unvaccinated.
    - kansface 5y ago
      I believe that number is in the 80s for the mRNA vaccines and lower for the others (minus the one from Russia).
      - tunesmith 5y ago
        There are many efficacy numbers. mRNA does help against infection but efficacy is apparently low, like 50-60%. Makes sense because they weren't really developed with that in mind. Efficacy goes to 60-80% for symptomatic, over 80% for serious/hospitalization, and mid 90% for death. I think.
  - tunesmith 5y ago
    Right, and that's where vaccine efficacy comes into play. If r0 is 6 and HIT is 83.3%, but efficacy is only 90%, then you actually need about 93% vaccinated. And for herd immunity, what matters is transmission, and the vaccine efficacies for asymptomatic infection are pretty low; 50-60%. So mathematically impossible without severe lockdowns and/or improved vaccines that are better at preventing transmission.
- polynomial 5y ago
  Do we have generally accepted R0 values for each of these 3 variants?
  - marricks 5y ago
    I think there's am R0 for initial strain and then ranges for the other variants. I thought it was in Wikipedia but either it's been edited out or I saw it elsewhere. What I recall (so huge grain of salt here) was R0 at 2.3 for initial strain then around 2x for Alpha and another 2-3x for Delta. Not. Great.
tehjoker 5y ago
Looking at the measles wikipedia article: "Furthermore, measles's reproductive number estimates vary beyond the frequently cited range of 12 to 18.[15] The NIH quote this 2017 paper saying: "[a] review in 2017 identified feasible measles R0 values of 3.7–203.3" https://en.wikipedia.org/wiki/Measles https://en.wikipedia.org/wiki/Measles