New Stanford C-19 IgM and IgG antibody test

New Stanford C-19 IgM and IgG antibody test - Printable Version

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New Stanford C-19 IgM and IgG antibody test - akiddoc - 04-04-2020

Stanford is conducting the first community surveillance testing to look at overall transmission in Santa Clara County. It is not randomized. I think this is an initial stab at seeing what is out there. Doing this in a randomized way throughout the country and in individual communities will give us a good picture of how things are going to play out.

https://www.mercurynews.com/2020/04/04/coronavirus-new-stanford-research-reveals-if-youve-been-exposed/

RE: New Stanford C-19 IgM and IgG antibody test - dabigv13 - 04-04-2020

Interesting that they do this with a finger stick not a blood draw which is typical for serology tests AFAIK. Certainly makes it easier for broad usage. Wonder if there is any sacrifice of accuracy.

RE: New Stanford C-19 IgM and IgG antibody test - OutsiderFan - 04-04-2020

This is the best news I’ve read this whole week. Thanks for sharing, and maybe we can keep updating this thread with results from the Stanford, Telluride and other antibody surveillance testing.

RE: New Stanford C-19 IgM and IgG antibody test - g1313 - 04-05-2020

It's interesting to note that this study (which I got my finger pricked for yesterday) is sponsored by the two Stanford Medicine professors who wrote an op-ed for the WSJ two weeks ago Is the Coronavirus as Deadly as They Say?

If the study comes back revealing that there is a very large population that have been infected asymptomatically, and therefore the fatality rate is an order of magnitude smaller than 1%, would that be a reason to lift some current restrictions?

RE: New Stanford C-19 IgM and IgG antibody test - magnus - 04-05-2020

(04-05-2020, 11:44 AM)g1313 Wrote: If the study comes back revealing that there is a very large population that have been infected asymptomatically, and therefore the fatality rate is an order of magnitude smaller than 1%, would that be a reason to lift some current restrictions?

I can't imagine so. The immediate goal is still to minimize the (over)load on the healthcare system. Critical cases are still critical cases even if the figurative bar to be considered a generic case changes.

RE: New Stanford C-19 IgM and IgG antibody test - M T - 04-05-2020

Dr. Maldonado, one of the Stanford Med School people doing this study, was on a Town Hall meeting about 11:30AM today (30 min ago). She said several things that I'll try to capture. (My apologies if I get something wrong or left out something. I didn't take notes.)

1. There are a number of antibody tests on the market. None of them has FDA approval. Stanford tested them and, if I recall correctly, found them unsatisfactory for Stanford's purposes. It is unknown (at least publicly) what it means if you get a positive result or a negative result on those tests. (I took that to mean what are the false positive & false negative rates, but perhaps it meant more than that.)

2. Stanford's test was approved by the FDA on Friday, and they ran these tests.

3. The meanings of the test will be determined by further studies. Such as,

if positive, are you immune to getting the disease again. If so, how long are you immune?
if positive, and you are exposed again, might you become infectious again (ie, potentially asymptomatic & infectious)

(Those may also be what Dr. Maldonado meant about they didn't know what the other test results meant.)

She did not say anything about any preliminary numbers or when any results would be available.

In the same town hall, Dr Cody (SCC Public Health director) indicated "6 feet is a minimum". She also said that her office does not have access to the number of recovered patients. She said that it had been expected that once the commercial companies started producing the tests, there would be plenty. This hasn't been the case. She doesn't know all the reasons why that is.

I didn't know the phone-based Town Hall was happening (Joe Simitian organized it. Anna Eshoo was next up on the call, but I left it) until I got an automated call that it was going on. It was in progress at the time I joined it.

I presume this is the Dr. Maldonado that was on the call.

RE: New Stanford C-19 IgM and IgG antibody test - M T - 04-05-2020

(04-05-2020, 11:44 AM)g1313 Wrote: It's interesting to note that this study (which I got my finger pricked for yesterday) is sponsored by the two Stanford Medicine professors who wrote an op-ed for the WSJ two weeks ago Is the Coronavirus as Deadly as They Say?

If the study comes back revealing that there is a very large population that have been infected asymptomatically, and therefore the fatality rate is an order of magnitude smaller than 1%, would that be a reason to lift some current restrictions?

As of yesterday, there were 300K known cases in the US, and the case count more than doubled in 6 days. The 1.8%(S. Korea) to 4.1% (China) to 12.3%(Italy) fatality numbers that are mentioned applies to that 300K (and the roughly 600K by Friday, 1.2M by tax day)

If you want to say that we only discover half the case because the other half are asymptomatic, then divide 4.1% by 2 and multiply 300K by 2 and then multiply the numbers and see what you get. Try 10 instead of 2....

You do the math, and let us know your recommendation.

RE: New Stanford C-19 IgM and IgG antibody test - BostonCard - 04-05-2020

(04-05-2020, 12:02 PM)magnus Wrote:
(04-05-2020, 11:44 AM)g1313 Wrote: If the study comes back revealing that there is a very large population that have been infected asymptomatically, and therefore the fatality rate is an order of magnitude smaller than 1%, would that be a reason to lift some current restrictions?
I can't imagine so. The immediate goal is still to minimize the (over)load on the healthcare system. Critical cases are still critical cases even if the figurative bar to be considered a generic case changes.

Agreed. One thing it would do, however, is give you much more confidence that there might be a substantial amount of previously unknown herd immunity out there. Let's take New York, as an example. There are currently 3,500 deaths or so. If the CFR was 1%, then that means that ~350,000 people have been infected (114,000 have been reported), out of a population of 20 million in New York, which is not enough to offer herd immunity. If the undetected prevalence is actually 10x higher (that is, the CFR is closer to 0.1%) then 3.5 million out of 20 have been exposed. Still not quite enough to offer herd immunity, but we are getting somewhere. If the CFR is closer to 0.06% as the authors of that piece surmise, then the number of infected so far is closer to 5.8 million and that might be enough to start to make a dent on the susceptible population, especially because we haven't yet reached the peak number of deaths.

I think, however, that we are a ways away from the total number of deaths in New York, and once we hit 11,400 deaths, it will be clear that a CFR of .06% will be impossible unless 100% of the population had already been infected.

My guess is that the truth will be somewhere in between. Everything I've seen has suggested that between 1/4 and 2/3 of cases are asymptomatic, and thus the CFR may well turn out to be less than 1%. But it looks to be substantially higher than 0.1%.

BC

RE: New Stanford C-19 IgM and IgG antibody test - oldalum - 04-05-2020

(04-05-2020, 01:19 PM)BostonCard Wrote: If the CFR was 1%, then that means that ~350,000 people have been infected (114,000 have been reported)

I have a question on terminology. In earlier discussions of the CFR, I was using the term as you do above (I was speculating that, due to what I thought would be a substantial number of asymptomatic or minimally symptomatic infections, that the CFR would be end up being put at less than 1%--which I still think will be true). But since then I've read elsewhere that this is more properly called the Infection Fatality Rate, and that Case Fatality Rate is a more ambiguous term that depends on how a case is defined (e.g., positive test; hospitalization; ICU transfer, etc.). Can anyone help straighten me out? Thanks!

RE: New Stanford C-19 IgM and IgG antibody test - dabigv13 - 04-05-2020

My sense is that prevalence is higher than expected, but by a factor of maybe 2 or 3 not 10. I'm guessing the actual fatality will be between 0.5 and 1% generally, locally higher in areas where health care systems are overwhelmed.

RE: New Stanford C-19 IgM and IgG antibody test - BostonCard - 04-05-2020

Closed populations like cruise ships offer a bit of a window into the CFR:

https://www.economist.com/business/2020/03/31/the-coronavirus-may-sink-the-cruise-ship-business?utm_campaign=the-economist-today&utm_medium=newsletter&utm_source=salesforce-marketing-cloud&utm_term=2020-04-01&utm_content=article-link-5

If there are 1000 on board, and 4 deaths, the lower bound of the infection fatality rate (assuming everyone has been exposed) is 0.4%. They don't give the number of positive tests, but if everyone who has "flu-like symptoms" has Covid-19, and no one else dies, they upper bound of the CFR is 2.1%. In all likelihood, some of the passengers without symptoms will be positive, so the infection fatality rate is somewhere in between.

You might have to make an adjustment for the age of the population, however.

I do hope that every passenger is tested by both PCR and serology, as this would give us the best estimate of how symptomatic people are, and the infection fatality rate (and case fatality rate).

BC

RE: New Stanford C-19 IgM and IgG antibody test - M T - 04-05-2020

(04-05-2020, 02:03 PM)oldalum Wrote:
(04-05-2020, 01:19 PM)BostonCard Wrote: If the CFR was 1%, then that means that ~350,000 people have been infected (114,000 have been reported)
I have a question on terminology. In earlier discussions of the CFR, I was using the term as you do above (I was speculating that, due to what I thought would be a substantial number of asymptomatic or minimally symptomatic infections, that the CFR would be end up being put at less than 1%--which I still think will be true). But since then I've read elsewhere that this is more properly called the Infection Fatality Rate, and that Case Fatality Rate is a more ambiguous term that depends on how a case is defined (e.g., positive test; hospitalization; ICU transfer, etc.). Can anyone help straighten me out? Thanks!

I have been using the terminology from this report:
Estimates of the severity of COVID-19 disease

Quote:Here we attempt to adjust for these biases in data sources to obtain estimates of the CFR(proportion of all cases that will eventually die) and infection fatality ratio (IFR, the proportion of all infections that will eventually die)

I appreciated separating out what could be measured early in this epidemic (known cases) from the unknown (number of unknown cases). Even today, if I get symptoms and the PCR test returns positive, we are seeing that I would have about a 20% chance of developing pneumonia and a 5% chance of needing to be in the ICU as a result of the disease. ( If I don't have symptoms at the time of the test, there is some not-well-documented chance I'll get symptoms. If I never get symptoms, the likelihood of the disease causing pneumonia or the ICU is 0%.)

There are several things left open to interpretation:

Cases: positive test? clinically diagnosed, what about those that died before testing?

Infections: How do you count the asymptomatic? I'm pretty sure you have to estimate it based on some sampling.
And, for COVID-19, do you treat all cases equally? Or do you need to account for age, gender, handedness, or whatever parameters you care to differentiate on. I've been assuming there are some unknown factors that will determine whether someone who gets infected actually shows symptoms or not. Are those factors something that can be found from the data? It might be that 90% of 90yo have symptoms and 20% of 2yo. Or maybe it isn't age dependent.

Deaths: Do you only count current deaths. H ow do you count future deaths? (you can just wait) How do you count deaths that weren't known whether they were from the disease or not? This was the number that (IMO) was not properly accounted for by the various reporting agencies (WHO, CDC), leading to very low CFRs.

So, (in my non-professional opinion) CFR should start with a known population (for instance, those with symptoms that got a positive test) and then estimate the deaths from that group only (don't count deaths of people that never had the test). Again, you can pull out interesting subgroups of that population, by age, gender, handedness,... Post-infection medical care will impact the CFR.

IFR is squishier. IFR is a function of the disease, a population, the medical care, the deaths, and a way to estimate the number of infections. It is an attempt to say how many people in a population that get the disease, die from the disease. The question is how do you count the asymptomatic, especially in a new disease. Even recently, we've seen researchers hypothesize vastly different asymptomatic to symptomatic ratios.

Then there's also what is called the attack rate, basically what percent of the population get an infection. For COVID-19, this would relatively large, if unchecked. Many places, by doing social distancing, are trying to lower this rate. Except by avoiding overrunning the medical system, the CFR and IFR would not be affected by social distancing.

(No, I am unaware of any relation of COVID-19 to handedness. That is just a stand-in for any of the other characteristics that one might use, but without actually being any specific one.)

Evidence from the Diamond Princess and from the Wuhan evacuation flights puts the number of asymptomatic approximately equal to the symptomatic, but were those typical of the general population? (I doubt the ages of the cruise customers is typical). There are some epidemiology studies of the spread that likewise concluded that there were about as many unreported cases as reported cases in China. (Frankly, I didn't dig into those so I don't know how they got that result. Uncharacteristically, I've just accepted that.)

RE: New Stanford C-19 IgM and IgG antibody test - BostonCard - 04-05-2020

Also, in Iceland, where they have tested widely (and without regard to symptoms), about half the patients who tested positive have been asymptomatic.

BC

RE: New Stanford C-19 IgM and IgG antibody test - Mick - 04-05-2020

(04-05-2020, 04:08 PM)BostonCard Wrote: Closed populations like cruise ships offer a bit of a window into the CFR:

https://www.economist.com/business/2020/03/31/the-coronavirus-may-sink-the-cruise-ship-business?utm_campaign=the-economist-today&utm_medium=newsletter&utm_source=salesforce-marketing-cloud&utm_term=2020-04-01&utm_content=article-link-5

If there are 1000 on board, and 4 deaths, the lower bound of the infection fatality rate (assuming everyone has been exposed) is 0.4%. They don't give the number of positive tests, but if everyone who has "flu-like symptoms" has Covid-19, and no one else dies, they upper bound of the CFR is 2.1%. In all likelihood, some of the passengers without symptoms will be positive, so the infection fatality rate is somewhere in between.

You might have to make an adjustment for the age of the population, however.

I do hope that every passenger is tested by both PCR and serology, as this would give us the best estimate of how symptomatic people are, and the infection fatality rate (and case fatality rate).

BC

I'd be curious to know their co-morbidities as well, prevalence of coronary disease, hypertension, lung disease, etc. I've only ever been on one cruise, but my general sense was that the presence of said factors was much greater than that of the general population.

RE: New Stanford C-19 IgM and IgG antibody test - M T - 04-05-2020

I'd be curious if the antibody test might get done on the known-infected tiger at the Bronx zoo (assuming such a test is meaningful in another species).

I suspect that they drugged the animals to take swabs from 6 of the big cats. I suspect they also took blood samples at the same time, and that some of such a sample might be used for this test.

RE: New Stanford C-19 IgM and IgG antibody test - BostonCard - 04-05-2020

Probably not. Most serology tests work by a sandwich method. Antibodies are composed of two parts; they have a variable region that recognizes the pathogen and fixed region that is common to all antibodies (but differs between species). The test has an antigen (protein) that's recognized by the antibody, and then a tag (ironically, itself mounted on an antibody that recognizes the fixed portion of the antibody). If you put another species' antibodies on the test, it is likely that the tag won't bind to it.

BC

RE: New Stanford C-19 IgM and IgG antibody test - Goose - 04-05-2020

(04-05-2020, 04:58 PM)BostonCard Wrote: Also, in Iceland, where they have tested widely (and without regard to symptoms), about half the patients who tested positive have been asymptomatic.

BC

Not quite right. The tests run by the government use somewhat similar criteria to the criteria used here. You get tested if you are symptomatic or if you have been in close contact with someone who has COVID-19. Such persons are more likely to test positive than a "random" individual. The tests run by deCODE Genetics (Amgen) are open to all. About half the tests run in Iceland have been run by deCODE. I do not know what test is being used by deCODE, or what controls they use. deCODE says they plan to test at least 50,000 individuals (13.7% of the population) before they stop.
https://reason.com/2020/04/03/what-we-should-have-learned-from-icelands-response-to-covid-19/

RE: New Stanford C-19 IgM and IgG antibody test - OutsiderFan - 04-06-2020

What is the population size needed to do random sampling and achieve a result that can be extrapolated to the general population with accuracy?

Wouldn’t you basically need to go door to door in a given residential area to collect blood samples? I mean everyone were asked to go to testing locations in Los Altos, wouldn’t you get a non-random sample that has high risk factors for complications or thought to have reason to believe they might have been infected, making it non-random?

My greatest question remains how do we end stay at home orders and not just have another massive outbreak when they are lifted. I see no evidence any country has fully gone back to normal without restarting virus spread. So many unknowns still, that not even antibody testing can fully answer, but hopefully it does get us closer to understanding WTF is going on.

RE: New Stanford C-19 IgM and IgG antibody test - burger - 04-06-2020

(04-06-2020, 03:41 AM)OutsiderFan Wrote: My greatest question remains how do we end stay at home orders and not just have another massive outbreak when they are lifted. I see no evidence any country has fully gone back to normal without restarting virus spread. So many unknowns still, that not even antibody testing can fully answer, but hopefully it does get us closer to understanding WTF is going on.

I'll give you the most pessimistic answer you'll see here: there is 0 chance of avoiding a second outbreak. Even if we get the numbers down via social isolation now, all you need is a few undetected cases to slip past, and we are right back where we started a few weeks after the movement restrictions are loosened. The federal government has offered no plans whatsoever for widespread testing and contact tracing. It's abundantly clear that trump is banking on a hail mary from cholorquine to save the day. When that fails (evidence points that way so far), he has nothing else to offer us.

The states lack the resources to implement the testing and contact tracing that would be necessary--maybe CA and NY could pull it off, but it will never happen in poorer states, and I doubt that CA can or would close its borders. So even if CA does it right (and I haven't seen any evidence they are working on post-peak planning yet), if AZ screws things up (their governor already waited weeks too long to shut down the state), it just takes a few cases moving from AZ to CA to set things off again.

Newsom is saying to expect restrictions until August or September, but I think even that is optimistic. I expect political pressure will result in things opening up by the fall or even the summer, but the virus will not be gone in the US, and there will be a second outbreak.

RE: New Stanford C-19 IgM and IgG antibody test - Mick - 04-06-2020

(04-06-2020, 07:23 AM)burger Wrote: It's abundantly clear that trump is banking on a hail mary from cholorquine to save the day. When that fails (evidence points that way so far), he has nothing else to offer us.

I think Remdesivir offers better odds. More a skinny post than Hail Mary...