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The mutation that helps Delta spread

nature.com

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Re: The mutation that helps Delta spread

#71

Post by tandem5000 »

erokar wrote: post #23
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…

Delta-infected patients seem to be 1.8 times more likely to be hospitalised, compared to Alpha-infected patients [1]. Since the covid virus takes two weeks plus to kill its host and also spreads while the host is asymptomatic, there really isn't much selective pressure to make it less deadly. So far infectiousness and severity of disease has gone hand in hand with this virus. 1. https://www.bloomberg.com/news/article…

> 1.8

What's the confidence interval?

Re: The mutation that helps Delta spread

#72

Post by polynomial »

chefkoch wrote: post #45

Can someone eli5 why some variants are substrains like Delta AY3 and what or how much has to change to have it declared as a new strain?

This is a really great question. Technically speaking, any single mutation defines a new strain. But that's not how we tend to talk about it either to the general public or amongst clinicians. Rather we use a more informal notion of a significant functional change. We do this because there is, somewhat surprisingly, no real term that reflects the category of "new strain with significant or interesting functional effects."

Re: The mutation that helps Delta spread

#73

Post by polynomial »

desine wrote: post #58
OneLeggedCat wrote: post #41

Earlier quoted context omitted.

> 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.

weakened how?

Re: The mutation that helps Delta spread

#74

Post by tomrod »

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").

It comes from the same family as SARS and MERS. Worst case, IMHO, would be that level of mortality combined with its current R0 of 6 to 9.

Re: The mutation that helps Delta spread

#75

Post by tunesmith »

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.

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.

Re: The mutation that helps Delta spread

#76

Post by aantix »

hncurious wrote: post #70

Covid is going to be endemic like the flu and cold. It's not going to be eradicated, unfortunately, and I don't think we've come to terms with this yet. Now what's our plan exactly? Get vaccinated every 6 - 12 months indefinitely and always wear masks? What's our goal and what's our new normal?

Take Vitamin D/C/Zinc/Niacin and build up natural immunity?

Re: The mutation that helps Delta spread

#77

Post by cmrdporcupine »

hutzlibu wrote: post #61

I see the sentiment here expressed, that Covid is far from over. To be honest, I stopped following news since being fully vaccinated some time ago, so I am kind of ignorant here. Is the main problem, the unvaccinated, or that the Delta (and co.) variants are still, too dangerous for vaccinated people? Or is it the fear, that they will get more dangerous?

So here in Ontario where we're @ about 65% of the population totally vaccinated, today's new cases.

Source: https://data.ontario.ca/dataset/covid-19-vaccine-data-in-ont...

10.25/100k among people who are unvaccinated. 6.5/100k among people who are partially vaccinated. 1.0/100k among people who are fully vaccinated.

For hospitalization:

2.04/100k for unvaccinated, 1.11/100k for partially, 0.21/100k for vaccinated.

For current ICU status:

1.6/100k for unvaccinated, 0.7/100k for partially, 0.05/100k for vaccinated.

So basically the vaccines are really good, even against Delta. The disease is spreading primarily among the unvaccinated. And even those who get it who are vaccinated are on the whole not getting very sick.

EDIT: For those wondering about natural immunity: only 3.67% of the Ontario population is counted as having had COVID, so I doubt it's a significant influence on those statistics. Granted, the first wave had poor testing, so I'm sure the number is a little higher, but I doubt it's more than 5%.

EDIT: disregard the below comment about 10% ending up ICU; is incorrect because I was comparing the incremental new case count against current ICU status. I'll try to fix the # in a bit.

But what's kind of crazy is seeing that those numbers seem to be saying that among the unvaccinated who get it that almost 10% of them are ending up in ICU. And when you consider that those are probably overwhelmingly young people (here 92% of seniors are fully vaccinated and 95% at least one dose) that's scary.

Re: The mutation that helps Delta spread

#78

Post by DSMan195276 »

nradov wrote: post #60
bredren wrote: post #34

Earlier quoted context omitted.

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 h…

> 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.

Just curious about this point - wouldn't this always be the case, since before it was good at infecting humans it would only be in a few if any of them? IE. My thinking is that even if it had existed for a while before that point, we'd be unlikely to know since it wasn't at that point good at infecting humans and thus not many had it.

Re: The mutation that helps Delta spread

#79

Post by tehjoker »

nradov wrote: post #60
bredren wrote: post #34

Earlier quoted context omitted.

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 h…

SARS-CoV-2 is a generalist that can infect many animals. I doubt it a "lab leak". Studies of genetic sequences from around the Wuhan fish market showed that it had been circulating and mutated a bit for some time before it was detected.

Re: The mutation that helps Delta spread

#80

Post by sdze »

hncurious wrote: post #70

Covid is going to be endemic like the flu and cold. It's not going to be eradicated, unfortunately, and I don't think we've come to terms with this yet. Now what's our plan exactly? Get vaccinated every 6 - 12 months indefinitely and always wear masks? What's our goal and what's our new normal?

Too bad that the cold and influenza flu are not comparable with Covid-19.
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