The New York Times

The New York Times 8 May 2020

How Does Coronavirus Antibody Testing Work?


Stanford Health Care gave us exclusive access to show how coronavirus antibody testing works. So we followed two caregivers and their blood, through the testing process.

Large scale antibody testing is underway in California as labs across the country work to develop their own versions. Aired on 4/13/2020.
Coronavirus antibody tests have become widely available across the United States, but the effectiveness and reliability of such tests remain in question. They can be used to determine if someone has been exposed to the coronavirus and developed antibodies against it, which could indicate some immunity. (April 28).
In the fight against the coronavirus, there is still one big unknown: how many people have actually contracted it, maybe even without showing any symptoms? One way to answer this question is through antibody tests. An antibody is a protective protein produced by the immune system to destroy harmful viruses and infections. When a pathogen enters the body, the immune system recognizes it and produces antibodies that dock onto the pathogen's antigens to remove them. Later a blood test can be used to detect these antibodies in a person's blood stream. Antibodies are also used in vaccines to make people immune to future infections. But immunity doesn't last a lifetime in all cases. So what do we know about Sars-CoV-2? How long will people be immune after an infection?
The UN says prisons across Latin America are overcrowded and a breeding grounds for the coronavirus. We have heard similar warnings here in Europe. Germany has prevented outbreaks in its prisons by releasing prisoners. Up to a thousand inmates have gone free. DW Reporter Amien Essif has been speaking with prisoners, however, who paint a very different picture of what is going on behind bars. Are prison authorities making a trade-off between prisoners' rights and their safety?

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As time goes on, more people are wondering,
did I have coronavirus already.
"I can help the next patient [INAUDIBLE]."."
Now, Stanford hospitals in northern California
are giving their health care workers
the answer with antibody testing for all.
We were given exclusive access to follow
two caregivers and their blood through the antibody testing
"I do have a loved one at home, my mother,
who is high risk.
So I want to get tested just to make sure I'm O.K.,
and kind of maybe surprise her and say, I
get to come see you."
First, they're swabbed to make sure they're not
currently infected.
"Oh my god."
And then they give a vial of blood for the antibody test.
"There's so many asymptomatic carriers around,
and there's so many people that may have had it
or had mild symptoms, and not had known.
If I have the antibodies and someone needs my plasma,
I'd love to help out."
"Honestly, I'm hoping that comes back positive,
that it'll teach us a lot."
"--the blood antibody test for the COVID-19 virus."
This blood test, also known as serology,
will show if they had coronavirus in the past,
and their immune system raised antibodies to fight it off.
But it can't predict if those antibodies
will make them immune.
What this and other reliable antibody tests can do
is give us a better picture of how widespread coronavirus
actually is.
And they're helping researchers
design possible treatments and vaccines.
"More widespread testing will help us to better understand
more quickly what are the important variables,
you know, who's going to be protected, who's not."
These are samples from the people we just met including,
Heidi and Jamshid.
Here, they'll be spun to separate blood cells
from plasma.
Next, that plasma is taken to a different lab
on campus for analysis.
"You can see the robot is precisely
putting in the right amount of each sample
into the wells of the plate."
"There's been great demand for the test.
The lab is basically open 24 hours.
The instruments have been running day and night."
Dr. Scott Boyd and his team developed this test,
and now they're ramping up quickly.
They've just received a new shipment of robots
called ELISA Instruments.
Soon, the team hopes to process
at least 4,000 samples a day.
They use controls to validate their tests,
so they know it works.
The positive controls are from coronavirus patients
at Stanford, and the negative are
from healthy blood donors, taken before coronavirus
jumped to humans.
Out of 200 people, the results for a few may be inaccurate.
But this kind of test is among the best we have.
You can see the controls here in the left column
of each assay plate.
Once the plate finishes processing,
you can see a yellow color in the patient samples
that have antibodies.
The darker the color, the more antibodies there are.
"But just measuring the total quantity doesn't tell you
all the information you'd like to know.
The question is, does somebody likely have immunity.
The answers are not yet as clear."
Only some antibodies actually fight or neutralize
the virus.
So the next step for researchers
is to identify those ones.
Then, how much of those neutralizing antibodies
are needed to block the virus and prevent re infection?
"So we're also now working on developing a neutralizing
anybody test that would allow us
to test a lot of patients in the hospital,
and also health care workers."
That neutralizing antibody test,
which Dr. Boyd hopes to have ready by the end of May,
will give a better sense of who is actually immune.
Remember Heidi from earlier?
Well, we watched her sample go through the process.
And now her results are in.
"Not detected."
All right, so what did the results say?
Negative COVID and negative serology, unfortunately.
But it's a good thing, right?
It can still be good.
Today's really my only safe day,
because I go back to work tomorrow.
So I feel pretty safe that I can go over, see
my mom without a mask.
I don't think she's got the ability
to survive a disease like this,
so I've had to be very careful.
I haven't seen her face.
She hasn't seen my face without a mask on since like,
the beginning of March.
I'm negative."
"You get to take your mask off, at least for today.
Come out here."
"Oh my goodness.
I'm so happy."
"I missed you."
"I missed you.
Oh, I haven't had a hug forever.
Oh, I'm so happy.
O.K. Bye bye, sweetheart.
Bye bye."
"All right.
Bye bye."
"Thank you."
Jamshid's results are the same as Heidi's
"So I do not have the antibodies, which is great,
because it means PPE works, which is fantastic.
I've definitely been in multiple rooms
with people with known COVID, and I've been wearing PPE.
And I'm glad that I was at a place
that I didn't have to reuse or recycle my PPE."
Preliminary data is starting to show
that Heidi and Jamshid's negative antibody results
are representative.
"Hi, Romey."
In places like the Bay Area that haven't been hard hit,
only a small fraction of people
are testing positive for antibodies.
"You know, where I go to the grocery store, I get it.
I go to work again, I get it.
It's out there, so I'm still going
to take the same precautions.
I'm going to still wear a mask."
But these tests are a first step towards understanding
Just having antibodies is not a free pass.
"Hopefully if someone's positive,
it doesn't give a false sense of security.
I still think that everybody needs
to protect themselves just the way that we currently are."

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