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The mutation that helps Delta spread

nature.com

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Re: The mutation that helps Delta spread

#51

Post by nemo44x »

slumdev wrote: post #25
selimthegrim wrote: post #15

Earlier quoted context omitted.

Uh... citation? And as you know, neutralizing response is not the only type.

A study demonstrating the mechanism for Delta ADE in vivo: https://pubmed.ncbi.nlm.nih.gov/34384810/ Highly-vaccinated Israel's third-wave surge in both cases and deaths: https://www.worldometers.info/coronavirus/country/israel/ Unvaccinated Palestine's lack of third wave deaths: https://www.worldometers.info/coronavirus/country/state-of-p...

A couple things though - the median age of Israel is higher than that of Palestine by a pretty large margin. Secondly, how can we be sure both places are testing at the same rate? For instance, the percentage of cases reported in Palestine VS Israel is smaller when adjusted for population size.

Re: The mutation that helps Delta spread

#52

Post by [deleted] »

slumdev wrote: post #25
selimthegrim wrote: post #15

Earlier quoted context omitted.

Uh... citation? And as you know, neutralizing response is not the only type.

A study demonstrating the mechanism for Delta ADE in vivo: https://pubmed.ncbi.nlm.nih.gov/34384810/ Highly-vaccinated Israel's third-wave surge in both cases and deaths: https://www.worldometers.info/coronavirus/country/israel/ Unvaccinated Palestine's lack of third wave deaths: https://www.worldometers.info/coronavirus/country/state-of-p...

[deleted]

Re: The mutation that helps Delta spread

#53

Post by Retric »

nradov wrote: post #37
marricks wrote: post #29

Earlier quoted context omitted.

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…

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-immu... Fortunately the vaccines are very effective at preventing death for all variants.

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.

Re: The mutation that helps Delta spread

#54

Post by achenatx »

cjfd wrote: post #24
nonbirithm wrote: post #6

Is it implausible to think that continued transmission and mutation at this rate will cause a catastrophic worsening of the pandemic to an extent several orders of magnitude above what it is now? Vaccination is effective in the current state of the pandemic, but what's to prevent the built-up immune response of humankind being wiped out if the virus adapts enough?

Both the worst-case and the best-case scenario are on the table. Only time will tell what happens. As you seem to be focusing on the worst-case scenario I will talk about the best-case scenario. The best-case scenario is that the human immune system is getting used to corona with even vaccinated people spreading the delta variant with little chance of getting very ill. This will turn covid-19 into something like the…

The likely scenario is that it turns into cold/flu.

Everyone either gets the vaccine or the virus and we are all mostly immune. It mutates a little and once it mutates just enough to spread substantially everyone who gets it gets immune. Only a fraction of the population will get any particular mutation.

I remember having the debate that herd immunity has never happened without a vaccine. Which is just BS. Every disease throughout history has eventually reached equilibrium with humans which is essentially herd immunity.

Most mutations are point mutations. Once enough point mutations accumulate that give the virus superior ability to spread, it will. It is unlikely that any point mutation will suddenly make the virus orders of magnitude more deadly.

Re: The mutation that helps Delta spread

#55

Post by FooHentai »

walterbell wrote: post #13

Since the deadliest virus mutations kill their hosts, weaker virus mutations can spread (without killing their hosts) more quickly. US deaths peaked in January 2021, before Delta became prevalent in the US, before substantial vaccination, https://www.worldometers.info/coronavirus/country/us/#graph-... US daily vaccines peaked in April 2021, https://ourworldindata.org/grapher/us-daily-covid-vaccine-do... India (origin…

There are some confounding factors to that though, I think? Infectivity post mortem (as seen with plague) and time lag between infectivity and symptoms appearing allowing for longer periods of asymptomatic transmission. Both variables that mean the spread of a mutation and it's lethality need not be linked.

Re: The mutation that helps Delta spread

#56

Post by Sohcahtoa82 »

nradov wrote: post #37
marricks wrote: post #29

Earlier quoted context omitted.

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…

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-immu... Fortunately the vaccines are very effective at preventing death for all variants.

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.

Re: The mutation that helps Delta spread

#57

Post by walterbell »

cogman10 wrote: post #49
walterbell wrote: post #27

Earlier quoted context omitted.

> Early data from Scotland indicated that delta-infected Covid patients were 1.8 times more likely to be hospitalized than those with an alpha infection. Other U.K. data support the increased risk of hospitalization but do not provide clear evidence that delta patients experience more severe illness once in the hospital. How do hospitals identify individual patients infected by Alpha, Delta or other variant? Do they…

Not every nation does this, mostly only the ones with socialized medicine are. For nations like the US, we are measuring the variant by looking at sewage. It doesn't tell us anything about who ends up hospitalized, but it does give us a good indication of what the is the common variant in a community (and inferences are drawn from there). The UK has been doing probably the most covid genome sequencing of any nation.

Thanks, good to know. Would be interesting if the UK also measured variants via sewage, as a methodological comparison against their more expensive individual sequencing.

Re: The mutation that helps Delta spread

#58

Post by desine »

OneLeggedCat wrote: post #41
slumdev wrote: post #8

Earlier quoted context omitted.

SARS-CoV-2 has four antigens. The existing vaccines stimulate the production of antibodies against only one of them, the spike protein. The existing vaccines are proving ineffective against Delta because it has mutated significantly enough that its spike protein does not cause a neutralizing immune response. They may even be causing ADE, as evidenced by the most recent data comparing Israel and Palestine.

> existing vaccines stimulate the production of antibodies against only one of them Is this true for the J&J vax as well?

Yes the J&J shot still works using only the spike protein. IIRC only Novavax uses traditional inoculation of using the weakened SARS-CoV-2 virus.

Re: The mutation that helps Delta spread

#59

Post by polynomial »

marricks wrote: post #29
tehjoker wrote: post #22

Earlier quoted context omitted.

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

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…

Do we have generally accepted R0 values for each of these 3 variants?

Re: The mutation that helps Delta spread

#60

Post by nradov »

bredren wrote: post #34
tehjoker wrote: post #2

Is there any information on what the upper bound might be on the infectivity of SARS-CoV-2? I think a lot of people just assume one big jump consumes most of the range, but we've seen at least three big jumps so far ("Doug", "Alpha", and "Delta").

This is getting at “saying the quiet part out loud.” For a variety of reasons media and influential organizations have avoided considering the upper bound on virility and mortality (? Not sure the right term) of covid. But to think delta is it would be some kind of miracle. It would mean we are going through the worst of it, and that after we handle delta globally, people can worry about other things. But it doesn’t…

SARS-CoV-2 has multiple animal reservoirs, and that's one reason why it will be impossible to eradicate. But generally variants that evolve in animals will select for fitness in those different species. So those will probably have less impact on humans.

This is one piece of circumstantial evidence why some virologists suspect the virus was produced in a lab doing gain of function research using transgenic mice with human like respiratory systems. When the virus first appeared in Wuhan it was already really good at infecting humans. That would be unlikely if it had evolved in wild bats or pangolins and then jumped straight to humans. But we don't know for sure, maybe it was just natural bad luck with no lab involved.

https://pubmed.ncbi.nlm.nih.gov/25589660/

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