[absherwin]

This is an antibody test which will only be positive days after the onset of symptoms.

This is principally useful for several purposes:

1. Figuring out who to isolate in hospitals if the RNA test isn't available in sufficient quantity

2. Understanding who has already recovered from COVID-19 and is thus immune with all that implies in terms of inability to spread the disease and reduced need for PPE

3. Enabling us to confirm continued immunity later this year and understand how long the recovered will remain immune

This is not unique to this company. It's unclear to me whether the price is meaningfully less than competitors.

This thread is helpful for further understanding of the test and its utility: https://twitter.com/NAChristakis/status/1240689953895411714

Two more helpful references: State of testing techniques as as of a week ago: https://sph.nus.edu.sg/wp-content/uploads/2020/03/COVID-19-S...

The paper on which this test is based: https://onlinelibrary.wiley.com/doi/pdf/10.1002/jmv.25727

[gridspy]

Bear in mind in relation to immunity -- "Positive results may be due to past or present infection with non-SARS-CoV-2 coronavirus strains, such as coronavirus HKU1, NL63, OC43, or 229E."

[calvinmorrison]

Those are the most common corona viruses strains that cause symptoms of the common cold (which itself is caused by something like ~200 known different viruses, the most prevelant being rhinoviruses). I was under the impression many people already had these antibodies

[teruakohatu]

Slightly off topic question: do people who have been infected with those varieties have any sort of immunity against covid-19?

[hedora]

Some health professional floated the theory that kids aren’t getting it as much as the rest of the population because they’ve recently been hammered with all the coronaviruses at daycare.

I’m hoping this is true, since it suggests new parents are mostly OK too.

[yokaze]

The theory I've heard: Children mostly rely on their innate immune system compared to adults, where the adaptive immune system is more fully developed. In elderly people, the immune response of both systems is slower/weaker.

[ummonk]

I keep searching for animal studies on this and come up empty - all I can find is some studies on serological cross response when testing people for SARS exposure.

Vaccines are obviously the best bet, but I wonder whether deliberately exposing the healthy to common cold Coronavirus might improve herd immunity against this Coronavirus. E.g. maybe in late summer it can be used to forestall a second wave of Coronavirus spread in the winter.

[freeone3000]

Do it like we did smallpox? Worth a shot...

[teddyvangogh]

No immunity. but they develop antibodies. More info here:

"FDA is working on treatment of coronavirus with blood from recovered patients"

"The method — essentially harvesting virus-fighting antibodies from the blood of previously infected patients — dates back more than a century"

https://www.nbcnews.com/health/health-news/fda-working-treat...

[Aperocky]

Potentially.

If true, we might rush to get everyone cold and then be immune to coronavirus.

[acqq]

From the last paragraph before conclusion of their article:

"Certainly, this test cannot confirm virus presence, only provide evidence of recent infection, but it provides an important immunological evidence for physicians to make the correct diagnosis along with other tests and to start treatment of patients. In addition, possible cross-reactivity with other coronaviruses and flu viruses were not studied, and the change level of antibody was not compared in the different stages of SARS-CoV-2 infection."

[absherwin]

This preprint explores, in part, cross-reactivity for a similar test and found it to negligible: https://www.medrxiv.org/content/10.1101/2020.03.17.20037713v...

[joe_the_user]

This is an antibody test which will only be positive days after the onset of symptoms.

This isn't really what your Twitter link says. That links says: "Both IgM & IgG (those are two different kinds of antibodies, with IgA being a third) were low or undetectable at day 0, but increased by day 5 in nearly all patients (N=16)"

-- Reports strongly indicate there are many infected people who are asymptomatic after five days.

Which is to say, this test could be extremely useful if applied widely and systematically to many people; food service workers, health care workers and so-forth.

Currently the virus test has a week turn around time. So both tests effectively find people with a week's exposure.

[nosuchthing]

Turn around time is mostly due to shipping samples to outside labs, in addition to outside labs lacking automation.

[joe_the_user]

But that doesn't change the current situation.

Even you could change that, just cost would make this approach very useful.

[saym]

Does "N=16" mean they've approved this test after such limited testing?

I think my high school stats class told me not to trust studies where N < 30.

[__blockcipher__]

I think the acceptable value for N depends on the size of the effect being studied.

For example if it’s a massive effect, maybe 10 people is sufficient, but if it’s tiny enough to get swallowed up in statistical noise until you have 1000, then you need N >= 1000

[Bnshsysjab]

I would be told off if I coded with magic global variables and is why I find math and bio frustrating. Care to explain the purpose of N?

[411111111111111]

Its the number of people they used to test.

[pas]

Is this test able to detect that someone is infected before they start to infect others?

[DanBC]

No. This test tells us that you had covid-19 in the past and recovered from it.

[pfranz]

> 2. Understanding who has already recovered from COVID-19 and is thus immune with all that implies in terms of inability to spread the disease and reduced need for PPE

I've been looking forward to seeing this kind of test just for this reason so we can whitelist people. But since a large percentage of people don't have symptoms how can you tell if you're still shedding the virus?

[rflrob]

I assume if you test positive for the antibody and N days later test negative for the virus, you’d be in the clear to be whitelisted.

[supdatecron]

> will only be positive days after the onset of symptoms.

If you're asymptomatic, would it also be positive?

[dogma1138]

Yes since it’s an antibody test.

[eps]

Hold on. Has it been confirmed that recovered people do in fact develop immunity?

[dmurray]

It's ok to take that on faith. If you recover from the virus, it's because your immune system knows how to kill the virus. We don't know of any immune system interactions that don't work that way.

There's a chance that immunity is short-lived, or that there are multiple strains of the virus which do not produce equivalent antibodies, but 100% of scientists will believe you develop immunity of some sort.

[istorical]

> We don't know of any immune system interactions that don't work that way.

Unfortunately not the case. https://en.wikipedia.org/wiki/Antibody-dependent_enhancement

But the good news is that we don't have any knowledge of coronaviruses that get worse the second time around because of ADE.

[dmurray]

Isn't that a case of having multiple strains of the virus, where recovering from one strain still provides immunity to that strain? The gimmick here is that it decreases resistance to the other strain, possibly after some time.

[HenryBemis]

I was hearing some doctors saying on the radio that any flu immunity is short lived, this is why we need to have the anti-flu vaccinations every year, that cover the typical/usual strains. If immunization lasted forever there wouldn't be a need for annual vaccination.

[dharma1]

rhesus monkeys do - https://www.biorxiv.org/content/10.1101/2020.03.13.990226v1....

[jakear]

I think its almost certain that if it were possible to be re-infected (at least in short timescales), it would have happened by now, somewhere.

[macintux]

There have been reports, but it’s not to my knowledge clear whether the people who’ve tested positive after being considered recovered were experiencing something else, like a false positive before/after, or weren’t in fact fully recovered.

[deelowe]

Running theories so far are that those were relapses, not reinfections.

[marcosdumay]

4. Measuring what share of people actually develops the disease so we can model forward the spread of the virus.

5. Identify whether there are riskier subpopulations or if everybody is on the same risk level.

[burtonator]

I'm interested in the frontline response here as if you already have immunity that person can serve in "risky" positions like working at airports, etc.

[anonuser123456]

Serious question: can an employer discriminate based on immunity status?

My personal opinion is absolutely. But I'm 99% certain a vocal minority will spoil it for us.

[jrockway]

I am pretty sure there is a list of things that employers (in the US) can't discriminate on, and immunity to Coronavirus isn't one of them.

I think it will ultimately be in the hands of workers to decide whether or not they want to do the job. Maybe I'm immune to Coronavirus so I should work in a pharmacy... but I get paid 10x as much writing software, so I'm probably going to do that instead.

[Bnshsysjab]

What if you’re immunocompromised with a hereditary illness? If there’s reasonable grounds it makes sense but reasonable and what employers will try and get away with are two different things.

[BurningFrog]

A test for who is immune seems very important a few months down the road!

[munk-a]

Oh that's easy - just find one of those Floridian beach goers. Anyone still fine in three weeks is immune.