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Covid-19: The T Cell Story

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Re: Covid-19: The T Cell Story

#121

Post by hcknwscommenter »

nodamage wrote: post #27
thewarrior wrote: post #21

Earlier quoted context omitted.

I think you’re being too negative here. I’m not an expert. My understanding is given that there is a pre existing T cell response that doesn’t mean that you will not be infected or that you will not have antibodies if infected. However it could totally be possible that when infected you are much less likely to show symptoms,die or spread it to others. It’s a tough hypothesis to completely verify but the dip in deaths…

I'm not sure what exactly you think is negative? The claim that infections top out at 10-20% is clearly not true. Even if it were true, we don't really know enough yet to conclude that T-cells would be the reason why. > It’s a tough hypothesis to completely verify but the dip in deaths and infections in many places in spite of lifting lockdowns lends some support to this theory. This sounds like a pretty weak correla…

No one claimed infections "top out" at 10-20 %. I agree, that is CLEARLY untrue. Rather, they seem to "level off" at 10-20%. That is, the rate of spread/new infections stops increasing so fast. Exponential infections always follow an S curve, but usually the leveling off of new infections starts at much higher penetration levels (e.g., 50%).

Re: Covid-19: The T Cell Story

#122

Post by hcknwscommenter »

lymeeducator wrote: post #11

T cell responses are interesting. Infectolab ( https://www.infectolab-americas.com/ ) and its originator Armin (Germany) are using T cell responses for tick borne diseases like: Borellia (Lyme), Bartonella and Babesia because antibody testing is difficult for these (broken via CDC specs as most labs won't test key proteins 31, 34 and never indicate which antibodies are present). Bartonella is very hard to test for wi…

Where do you live where you have a single doctor with 50 PCR+ COVID patients who have been tested for antibodies? Bergamo?

Re: Covid-19: The T Cell Story

#123

Post by hcknwscommenter »

Animats wrote: post #22
Animats wrote: post #7

The author asks some questions which can be answered by gathering some data. This suggests going back and re-testing for antibodies some populations from tightly packed groups - the cruise ship passengers, warship crew, and nursing home residents. The antibody tests are more accurate than they were two months ago. The key here is to find out how many people, definitely exposed to the virus, not only did not show any…

It looks like that's already been done, and there are tightly packed groups where the infection rate was 70-100%, as mentioned above. So, no existing immunity at all, probably. That was the claim in the original article, but the data does not bear it out.

70% infection Suggests a LOT of pre-existing immunity.

Moreover, even if 100% antibody + rates does not rule out a lot of pre-existing immunity. If I am naturally resistant to coronavirus (e.g., COVID patient sneezes in my face and I get a mild fever 10 days later), I'll probably develop antibodies from an exposure and otherwise be fine, I'd call that pretty damn good pre-existing immunity. According to your logic, that would be "no [pre-]existing immunity at all."

Re: Covid-19: The T Cell Story

#124

Post by hcknwscommenter »

jacobush wrote: post #61
Animats wrote: post #7

The author asks some questions which can be answered by gathering some data. This suggests going back and re-testing for antibodies some populations from tightly packed groups - the cruise ship passengers, warship crew, and nursing home residents. The antibody tests are more accurate than they were two months ago. The key here is to find out how many people, definitely exposed to the virus, not only did not show any…

The article specifically points out that there could be herd immunity in a certain population without any antibodies .

Yes, but that doesn't mean those people won't go on to develop antibodies if exposed to a significant dose, e.g., in a tightly packed community. It means they don't need to already have the antibodies to have a pre-existing level of resistance. It takes weeks to develop an antibody response from scratch.

Re: Covid-19: The T Cell Story

#125

Post by lsllc »

acqq wrote: post #52
lsllc wrote: post #36

Earlier quoted context omitted.

In Massachusetts (where we have been hit pretty hard by C19) we're trending downwards in a significant way and have been for a few weeks now. But I see more human activity out and about than ever (at least compared to March/April and mask wearing / social distancing is has been pretty obviously in decline for a number weeks now). The state is now well into it's re-opening phase 2 and even with the recent protests, th…

> Maybe the R0 curve just flattens more quickly than we thought? I think that's a confusion of R0 with Rt, Rt is what is influencing what we observe and simply not a constant, and additionally not the same in different settings or states: https://rt.live/ More importantly, for the Rt == 1 (and being constant) the number of cases would be constantly growing linearly . Only for Rt > 1 the growth is exponential. As long…

Thank you, I do mean Rt (being the R at time t) at least in the context of the current state of SARS-Cov2 for this discussion.

Re: Covid-19: The T Cell Story

#126

Post by lsllc »

remote_phone wrote: post #39
lsllc wrote: post #36

Earlier quoted context omitted.

In Massachusetts (where we have been hit pretty hard by C19) we're trending downwards in a significant way and have been for a few weeks now. But I see more human activity out and about than ever (at least compared to March/April and mask wearing / social distancing is has been pretty obviously in decline for a number weeks now). The state is now well into it's re-opening phase 2 and even with the recent protests, th…

I think what you’re seeing is exponential growth. Meaning, after crushing the curve, things start all over again with slow growth and then pick up again in 2 months. We are beginning to see the exponential growth explode in Arizona, Texas and Florida now I think.

I'm not sure how it's exponential, if you look at the graph for the current # of cases [0], then you can see it's more or less flat (and the new case %-age has been around 2-3%), between deaths and (most) people recovering, the number of active cases must at least flat and most likely getting smaller?

[0] https://en.wikipedia.org/wiki/COVID-19_pandemic_in_Massachus...

Re: Covid-19: The T Cell Story

#127

Post by nodamage »

hcknwscommenter wrote: post #113
nodamage wrote: post #9

> And wherever we look, infections level off before 10%-20% of the population is infected. This is somewhat mysterious. This is not really true. Bergamo had a 58% infection rate as of last month: https://bergamo.corriere.it/notizie/cronaca/20_maggio_22/ber... Several prisons have seen infection rates in the 70-80% range: https://www.npr.org/sections/coronavirus-live-updates/2020/0... The USS Theodore Roosevelt had an…

I'm not sure if your sources really say what you imply that they do. Bergamo had a 58% COVID exposure rate as of last month, as determined by serology studies. How many of those had a full blown infection? I suppose detectable antibodies suggests there was at least some level of infection, but a very mild infection plus rapid clearance in a plurality of the population fits with the sentence you quote. The other cites…

It was not my intent to imply anything about the severity of COVID infections, only that a 10-20% infection threshold is contradicted by several real world examples. While it is still possible that T-cells may have some immunological benefit against COVID, I don't think the 10-20% number qualifies as evidence of that.

Re: Covid-19: The T Cell Story

#128

Post by nodamage »

hcknwscommenter wrote: post #121
nodamage wrote: post #27

Earlier quoted context omitted.

I'm not sure what exactly you think is negative? The claim that infections top out at 10-20% is clearly not true. Even if it were true, we don't really know enough yet to conclude that T-cells would be the reason why. > It’s a tough hypothesis to completely verify but the dip in deaths and infections in many places in spite of lifting lockdowns lends some support to this theory. This sounds like a pretty weak correla…

No one claimed infections "top out" at 10-20 %. I agree, that is CLEARLY untrue. Rather, they seem to "level off" at 10-20%. That is, the rate of spread/new infections stops increasing so fast. Exponential infections always follow an S curve, but usually the leveling off of new infections starts at much higher penetration levels (e.g., 50%).

I mean, perhaps I misinterpreted the original article, but it sure sounded like the author was hypothesizing that T-cells confer immunity to a large percentage of the population which is why we were only seeing infection rates of up to 10-20% in the wild. I'm not sure his theory would make much sense if he actually meant "the rate of spread stops increasing so fast after 10-20% but continues up to 60% anyway".

Re: Covid-19: The T Cell Story

#129

Post by rstuart4133 »

kurthr wrote: post #50
lsllc wrote: post #36

Earlier quoted context omitted.

In Massachusetts (where we have been hit pretty hard by C19) we're trending downwards in a significant way and have been for a few weeks now. But I see more human activity out and about than ever (at least compared to March/April and mask wearing / social distancing is has been pretty obviously in decline for a number weeks now). The state is now well into it's re-opening phase 2 and even with the recent protests, th…

You're either exponentially growing or exponentially shrinking. (some) People are being more careful or wearing masks, which probably has a bigger effect on superspreader events than just "herd immunity". It slows the rise, but that doesn't mean that without intervention you have escaped the pandemic even though it was tamped down quickly. I agree that CA (especially NorCal) is probably over conservative... but only…

> You're either exponentially growing or exponentially shrinking.

That's what the math says should happen. It's not what the measurements say. If you look on http://91-divoc.com/pages/covid-visualization/ you will see country after country goes linear. The USA for example had 30k new infections most day for a remarkable 2 months.

I have no idea what causes it. It could be measurement error (that's what I first put it down to in the USA). But if it is it damned hard to explain why it has happened over and over again. Russia has been sitting on 9k new cases per day for 2 months now. The UK went through a period of 5k new cases per day for a month.

It's not a universal, or even the most common pattern. But it happens enough to make the statement "the measures of new covoid 19 cases always change exponentially" wrong enough to be effectively useless as a prediction of where things will head.

Re: Covid-19: The T Cell Story

#130

Post by acqq »

mlyle wrote: post #115
acqq wrote: post #59

Earlier quoted context omitted.

> then some mass spreading events infecting many more The point is however that it is impossible that the choir selected their members based on the criteria of "members can be only these who will be easily infected with the at the moment still unknown disease." There the existence of the superspreading event to "80% of some random selection" disproves the hypothesis that "on average much less than 80% of the populati…

We obviously have a huge variation in spread. Indeed, the choir is evidence of superspreaders who produce many cases, and we have an average R0 of 2-3. Singing loudly in enclosed spaces with many people is an example of a contact network structure that causes greatly increased susceptibility and contagion. Indeed, it proves the whole point! But, the belief that herd immunity = 1 - (1 / R) is based on the assumption t…

> There's been some quality analysis of time-series data that implies the threshold may be 20-30%.

Please provide the sources. I however don't expect it can be that good, and I'm quite sure it will be proven that it's impossible to expect for the epidemics to stop once 20 or 30% of the population is infected, if that is your claim. If your claim is that once that "threshold" is reached the speed of the spread changes, well that speed changed already much earlier: most people just don't have any motive to sacrifice for the "economy" or the rich or whatever. You don't need the laws for the people to figure out that much.

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