Curious, if these viruses are similar, how does an antibody test go about distinguishing between Covid-19 antibodies and other corona virus antibodies? In layman terms.

Quick math on this says it's still in the .6 percent range optimistically, with these numbers.

Right now Chelsea as had 39 deaths against a population of 40k, so they almost exactly at a .1 percent death rate already,
Adjusted for the overall population of a third are infected, that's a death rate of .3.
But among those already infected, how many more will still die? Let's just throw 11 more for a round 50 out there (yes, random stab) since deaths trail infections, and MA is around their peak. Then you have a death rate of around .36.
Then for the number of people in that study group who will eventually develop symptoms. If it's one third of those who haven't had symptoms, yet, then five cent of the overall population by their math that would fall into that category. Many of them will get tested and fall out of this study's range, Assume a .6 percent death rate on that five percent, and that is another .03 percent who will die. That makes the overall death rate around .4 percent.

But that doesn't account for the behavioral differences, those on the street taking this study are more likely to have been impacted than the largely shuttered population, how much is anyone's guess. But if you say 50 percent more likely and the two groups are equal in size (I completely accept that it's a random but might actually be conservative on both counts), then the death rate is .6.

At .6 with half the country infected (165 million), that is around 1 million dead. But plug your own numbers into that set of assumptions, it may be less, but it's still bad.

oragator said:

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But that doesn't account for the behavioral differences, those on the street taking this study are more likely to have been impacted than the largely shuttered population, how much is anyone's guess. But if you say 50 percent more likely and the two groups are equal in size (I completely accept that it's a random but might actually be conservative on both counts), then the death rate is .6.

At .6 with half the country infected (165 million), that is around 1 million dead. But plug your own numbers into that set of assumptions, it may be less, but it's still bad.

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Then you'd need to extrapolate something for the number of deaths for things like appendicitis while hospitals are beyond capacity

dermdoc said:

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Patentmike said:

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This suggests a less pathogenic variant is floating around. Doesn't prove it, but that's a likely answer.

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Disagree. Same virus, less virulent than thought. We have been driven by symptomatic cases which with respiratory viruses, is always the case.

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The study suggests that the infection rate in Mass is probably not far off from New York (possibly greater), but the Mass death rate is 1/4 to 1/3 that of New York (when considered per 1MM residents). A fairly common explanation would be a less pathogenic variant.

It's also possible that dosing has been much greater on average in New York, due to population density, explaining those differences.

Regardless of which it ultimately turns out to be, they should be looking for a variant.

TexjbA&M said:

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How so?

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See my response to DermDoc above.

But not zero.

So you're saying there's a chance.jpg

JP_Losman said:

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If it is that highly contagious it seems we can't stop It and should drop mitigation as long as we are prepped w hospitals

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Other reasons to attempt mitigation, better therapies may be developed soon & a higher prevalence in the community means more likely it gets into places like nursing homes and essential services like law enforcement. The numbers from the Smithfield plant illustrate how quickly a workforce can be infected.

https://www.nytimes.com/2020/04/19/us/coronavirus-antibody-tests.html

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Most of the tests offered are rapid tests that can be assessed in a doctor's office or, eventually, even at home and provide simple yes-or-no results. Makers of the tests have aggressively marketed them to businesses and doctors, and thousands of Americans have already taken them, costing a patient roughly $60 to $115.

Rapid tests are by far the easiest to administer. But they are also the most unreliable so much so that the World Health Organization recommends against their use.

Most are manufactured in China. Reports of countries that quickly bought millions have just as swiftly been followed by accounts of poor performance.

For example, Britain recently said the millions of rapid tests it had ordered from China were not sensitive enough to detect antibodies except in people who were severely ill. In Spain, the testing push turned into a fiasco last month after the initial batch of kits it received had an accuracy of 30 percent, rather than the advertised 80 percent.

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Not saying this is the case with the Massachusetts data in the OP, but with any breaking news reports about the serology test the question should be asked how reliable the data actually are.

Or they just learned some lessons from NY I how to treat

They likely did learn which is one of the reasons bending the curve was implemented

Patentmike said:

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dermdoc said:

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Patentmike said:

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This suggests a less pathogenic variant is floating around. Doesn't prove it, but that's a likely answer.

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Disagree. Same virus, less virulent than thought. We have been driven by symptomatic cases which with respiratory viruses, is always the case.

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The study suggests that the infection rate in Mass is probably not far off from New York (possibly greater), but the Mass death rate is 1/4 to 1/3 that of New York (when considered per 1MM residents). A fairly common explanation would be a less pathogenic variant.

It's also possible that dosing has been much greater on average in New York, due to population density, explaining those differences.

Regardless of which it ultimately turns out to be, they should be looking for a variant.

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You know a lot more than me and what you say makes a lot of sense.

I think the % across the board is most likely single digits but will of course vary between regions and outbreak centers....

I feel like the first paragraph of each of the studies needs to be discussing sensitivity and cross-reactivity before you read on to make sense of the data. Now we are just seeing too many different tests out there with their own quality compared to others making it very hard to compare studies and even anecdotal data unless you know who produced the test, etc

k2aggie07 said:

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Or the test they're using is unreliable. We haven't seen a paper from Mass, just this report.

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Yes, that's possible as well.

Moxley said:

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Yes, there are a few that have released data showing their efficacy and seem to be reliable.

The problem is once the FDA greenlit the EUA a whole bunch of other companies have flooded the market. There are apparently over 70 different fingerstick antibody tests on the market right now, many of which are coming from China. There are some hospital systems in the United States who are using tests manufactured in China. I'm concerned about those in particular being quite unreliable.

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Yes, do not trust anything from China. The country is at war with us. To lie, cheat, and steal is acceptable in their culture for the cause.

sounds like antibody testing is a non starter.
Nobody believes the results, junk test kits, probably actually cold virus etc etc.
Media not talking about these results in the slightest.

Back to the drawing board.

DTP02 said:

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From the article:

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He added: "Still, it's kind of sobering that 30 percent of a random group of 200 people that are showing no symptoms are, in fact, infected. It's all the more reason for everyone to be practicing physical distancing."

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It's amazing to me that so many, even in positions of leadership against the virus, miss the ball so frequently.

If the results bore out, it wouldn't be sobering news, it'd be great news. Just like the Stanford study in that regard.

I don't know how someone couldn't understand that, let alone someone in a relevant profession.

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They're worried about how much is spreading to those that can be severely affected while missing the good news there.

Media will pick up the stories, they usually lag a couple of days to week after publications.

Also, doesn't viral load matter? With New York, it seems that those exposed are likely exposed to a great amount. Their natural way of life is just a cesspool for germs compared to most of the country. The public transit, close quarters, etc.

So while it could be a different pathogen that's more severe, it could also just be the higher exposure to the same pathogen?

dermdoc said:

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Patentmike said:

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This suggests a less pathogenic variant is floating around. Doesn't prove it, but that's a likely answer.

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Disagree. Same virus, less virulent than thought. We have been driven by symptomatic cases which with respiratory viruses, is always the case.

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Not so fast...

All virus mutate eventually.
Preliminary test suggest Indian subcontinent has Covid 19 mutated variant less adhere to ACE receptor and less virulent possibly,

It bears out that despite massive population, death rate has been less in India...so may be?

JP_Losman said:

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If it is that highly contagious it seems we can't stop It and should drop mitigation as long as we are prepped w hospitals

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this is the answer - prepare our healthcare system and deal with the sick. Just like with the rest of life, people can make choices:

-some choose not to fly, because a plane may crash
-some choose not to drive or never make left turn, as they may crash
-some choose to not be around people during flu season - so they don't get sick
-some choose not to share needles or have unprotected sex, so they don't get HIV.

AgStuckinLBK said:

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That's positive news. My guess is we'll see the death rate from this thing is probably really 0.5% all comers.

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Based on the Stanford study, the death rate could ultimately range between 0.12% to 0.2%. Crazy low. I hope those numbers play out. We'll see.

So is this a valid study or is our test just not accurate enough to yield meaningful takeaways at this time?

From the manufacturer's website (https://www.biomedomics.com/products/infectious-disease/covid-19-rt/) :

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In order to test the detection sensitivity and specificity of the COVID-19 IgG-IgM combined antibody test, blood samples were collected from COVID-19 patients from multiple hospitals and Chinese CDC laboratories. The tests were done separately at each site. A total of 525 cases were tested: 397 (positive) clinically confirmed (including PCR test) SARS-CoV-2-infected patients and 128 non- SARS-CoV-2-infected patients (128 negative). The testing results of vein blood without viral inactivation were summarized in the Table 1. Of the 397 blood sample from SARS-CoV-2-infected patients, 352 tested positive, resulting in a sensitivity of 88.66%. Twelve of the blood samples from the 128 non-SARS-CoV-2 infection patients tested positive, generating a specificity of 90.63%.

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NorCal said:

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AgStuckinLBK said:

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fThat's positive news. My guess is we'll see the death rate from this thing is probably really 0.5% all comers.

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Based on the Stanford study, the death rate could ultimately range between 0.12% to 0.2%. Crazy low. I hope those numbers play out. We'll see.

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presuming a valid antibody is available & some of the tests appear to be quite good
the death rate should be available soon ( 6-8 weeks ) hot spots like St john parrish and Albany GA are small enough to do widespread testing then the death rate is pretty basic math.The Smithfield outbreak could also give some valuablle insight.

I am all for optimism, but NYC is already at .16 death rate across their whole population. And that's with more currently infected to pass away, and who knows what percentage actually infected who could still add to the numbers.
Not every place is the germ pit a big city like NYC is, but it is already proving worse than some of the more optimistic studies, at least the top ends of them. Less than .5 would be surprising at this point in the harder hit areas. Probably closer to 1, just my personal belief. We will see though. Hope I am overstating it.

JP_Losman said:

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Public faith in government scientists all institutions will be ruined after this event. Especially in epidemiology

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oragator said:

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I am all for optimism, but NYC is already at .16 death rate across their whole population. And that's with more currently infected to pass away, and who knows what percentage actually infected who could still add to the numbers.
Not every place is the germ pit a big city like NYC is, but it is already proving worse than some of the more optimistic studies, at least the top ends of them. Less than .5 would be surprising at this point in the harder hit areas. Probably closer to 1, just my personal belief. We will see though. Hope I am overstating it.

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This is what I keep coming back to. Is the IFR really going to turn out a lot different in NY compared to these other places claiming such low IFRs (based on these preliminary studies). What is it about NY State / NYC that would make the outcomes so much worse? Viral load because everyone's packed together? Overrun medical system (haven't seen this reported)? Demographics (NYC trends younger, no?)? What is it?

If the IFR really is near 0.1 like a lot of people claim, then NYC has basically a 100% infection rate or their IFR is an outlier for some reason?

Or I'm missing something, wouldn't be the first time.

Or NYC was the outcome for every major urban center, and was precluded by intervention. We don't know.

Can you clarify your position?
Not sure i understand what you recently posted?

Any chance the current swab tests are counting people who have colds instead of COVID-19 ?

JP_Losman said:

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Any chance the current swab tests are counting people who have colds instead of COVID-19 ?

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Depends on the test. They are testing for RNA virus via PCR. Any decent test will not throw significant false positives.

The titer tests are testing for presence of specific antibodies that responds to COVID only. I know my hospital has one that does NOT flip positive for other coronaviruses but I suspect many of the cheaper tests out there are showing positives for all coronaviruses.

In short-- not likely at least not more than 10% (hopefully). The larger concern with PCR testing is a possible high false negative rate due to poor sample collection.