An antibody test is a screening for things called antibodies in your blood. Your body makes these when it fights an infection, like
COVID-19. The same thing happens when you get a vaccine, like a flu shot. That’s how you build immunity to a virus.
You may also hear it called a serology test.
The antibody test isn’t checking for the virus itself. Instead, it looks to see whether your immune system -- your body’s defense
against illness -- has responded to the infection.
How Does an Antibody Test Work?
A technician will take a bit of your blood, like through a finger prick. The test looks for one or both kinds of antibodies to SARS-CoV-2,
the virus that causes COVID-19:
IgM antibodies, which happen early in an infection IgG antibodies, which are more likely to show up later WEBMD Life's Big Events:
Helping Older Adults Manage WebMD shares tips to caregivers about how to help loved ones as they get older. Most people have IgG antibodies
about 14 days after symptoms start. They usually stay in your blood long after the infection goes away, but we don’t know how long that
is for the new coronavirus.
What’s the Difference Between a Coronavirus Test and an Antibody Test?
A coronavirus test, sometimes called a diagnostic test, looks for signs of active virus. It’s simpler and faster than an antibody
test. But it tells you only if you have the virus in your body at the moment when you’re tested.
An antibody test shows that you had the virus at some point in the past. It could be gone, or you could still be contagious.
Why Do We Need Antibody Testing?
You could have SARS-CoV-2 and not know it. Not everyone who gets it has symptoms. Experts hope antibody tests can give health officials
a better idea of how common the virus is.
Once scientists know who has had the virus, they can find out how sick it makes most people. And they can study what happens if people
who've had it come into contact with it again. Along with other scientific information, this can help researchers understand who might
be immune to the virus.
The hope is that people with antibodies to COVID-19 can safely get back to work, and normal life, quicker.
These tests may also help with an experimental treatment for COVID-19 called convalescent plasma. Plasma is the liquid part of your
blood.
Researchers are studying how antibodies in plasma donated by people who’ve recovered from COVID-19 might help those who are ill with
the virus. Early research shows that this plasma may help sick people get better faster.
You can volunteer to donate plasma through the National COVID-19 Convalescent Plasma Project. Or ask your local blood donation center
for information.
Are Antibody Tests Accurate? Companies make their own claims about the accuracy of their antibody tests. Some say it’s up to 100%.
Government researchers are studying how well the tests are working, but it’s too early to say for sure.
The FDA says it will crack down on any manufacturer that sells a bad test.
It’s important to note that some tests can mistake IgM antibodies from other coronaviruses, such as common cold strains, for SARS-CoV-2
antibodies.
What Do the Results Mean for You?
If you test positive for SARS-CoV-2 antibodies, it probably means you’ve had the virus at some point of time. It’s also possible
to get a “false positive” if you have antibodies but had a different but close type of coronavirus.
If you are not sick a positive result means you have some immunity to the coronavirus. It’s too early to know how strong it is or
how long it might last.
A negative result means you haven’t come into contact with the virus or you haven’t had it long enough to make antibodies. You could
also have been exposed and not have antibodies. This is called a false negative.
No matter the result, if you don’t have symptoms, you don’t need follow-up. But if you do, you should take PCR diagnostic test to
look for signs of active virus RNA.
In March, as the United States faced a shortage of COVID-19 diagnostic tests to determine who was currently infected with the
virus, the Food and Drug Administration began allowing antibody tests into the country without FDA review or formal clearance.
A COVID-19 molecular diagnostic test, sometimes referred to as a virology test, is often conducted through a nasal or throat
swab. It is designed to detect if you presently have the COVID-19 virus.
A COVID-19 antibody test, or serology test, usually involves a blood sample and determines the presence of antibodies, which may
signal that you previously had the viral infection.
"The two different types of tests give us complementary information about the pandemic," said Dr. Alex Marson, an infectious
disease specialist and the director of the Gladstone UCSF Institute for Genomic Immunology. "The one tells us about who's
actively infected. The other tells us who has been infected."
Dr. Marson and Dr. Patrick Hsu, an assistant professor of bioengineering at the University of California, Berkeley both told 60
Minutes it is presently unknown if a positive antibody test means protection from future infection.
"We do not know if a positive antibody test means that you have protective immunity," said Dr. Hsu. "It will certainly mean that
in some cases, but how much, and for how long, and how many times? We do not yet know. People should not assume that, if you have
a positive antibody test that you're immune, [that] you don't need to wear a mask, and [that] you don't need to socially
distance."
A small sample size study from China published on June 18 in
Nature
Medicine
found antibodies could fade in as soon as two to three months after the time of infection.
Both Dr. Marson and Dr. Hsu were interviewed by 60 Minutes correspondent Sharyn Alfonsi as part of a three-month investigation
into the accuracy of antibody tests available in the U.S. The physicians assembled a team of scientists to study the accuracy of
COVID-19 antibody tests in early March.
The accuracy of antibody tests are measured by their sensitivity and specificity. The sensitivity refers to a test's ability
to determine if someone has COVID-19 antibodies present in his or her body. The specificity refers to a test's ability to
distinguish who does not have COVID-19 antibodies.
In the early months of the pandemic, hundreds of companies from around the world were selling antibody tests in the U.S. with
varying levels of accuracy.
In May, the FDA amended its policy and began requiring developers of antibody tests to apply for emergency authorization and
submit data to prove their tests work. The FBI
warns
the
policy change has not stopped scammers from trying to infiltrate the U.S. market with fraudulent or inferior quality tests.
The FDA also teamed with the other government agencies including the National Institutes of Health to track the accuracy of some
antibody tests and on June 18 published
performance
results
for 21 of them.
The FDA's list includes both rapid serology tests that are often processed on-location and tests that require blood samples be
sent to a laboratory.
ARRAY / AP
"I will say that the best tests, especially tests where blood samples are being sent off to labs, seem to have responsible test
performance characteristics," Dr. Marson told Alfonsi. "Does that mean that they're perfect? No"
The FDA says the prevalence of COVID-19 in a specific area and amongst different groups of people will factor into the likelihood
of false positive or false negative results.
"I think when you ever get a positive test, it's important to undergo confirmatory testing, whether with a different antibody
test, or an independent test that looks for a different viral antigen, or a different antibody isotype," Dr. Hsu told 60 Minutes.
"This will be a way that we can guard against false positives. The statistical likelihood that you would test false positive
twice is generally quite unlikely if you use independent tests."
Getting multiple independent tests might be more difficult than it sounds.
Quest Diagnostics and LabCorp are two of the largest laboratory testing providers in the U.S. They have collectively processed
more than 3.5 million COVID-19 serology tests.
Quest told 60 Minutes it presently offers antibody tests manufactured by Abbott Laboratories, EUROIMMUN AG, and Ortho Clinical
Diagnostics. LabCorp said it currently uses serology tests made by Abbott and Roche.
Both lab companies told 60 Minutes they do not allow patients to choose which antibody test is used ahead of a sample being
processed.
Quest said the testing platform used to process a sample depends on a lab's volume and capacity. The company said it can run
200,000 serology tests per day and has conducted 2.1 million since April.
LabCorp said it began serology testing on a limited basis in March and now has the ability to run 300,000 samples a day. It does
not disclose the daily volume of antibody testing, but told 60 Minutes it has processed approximately 1.4 million tests so far.
As of June 27, the Centers for Disease Control and Prevention
reported
more
than 32 million tests have been processed in the U.S. with a positivity rate of 9%. The CDC declined to tell 60 Minutes the
specific sources of its aggregated data. A spokesperson told 60 Minutes the 32 million tests include both viral and antibody test
results. The CDC also says not all test results are reported to them.
A Government Accountability Office
report
released
on June 25, 2020 says the watchdog agency found that the CDC has made mistakes in its collection of data about COVID-19 testing.
It says the CDC was gathering data about testing that combined antibody tests with diagnostic tests in their overall testing
numbers, a practice that has been criticized by scientists as mixing apples and oranges.
The CDC made an effort to correct this practice and advise states to separate virology and serology test results, but the overall
testing numbers from prior to June may still be inaccurate. Given the problems with accuracy of some antibody tests, it is also
unclear whether all antibody positives should be considered true positives.
The video above was produced by Keith Zubrow and Sarah Shafer Prediger. It was edited by Sarah
Shafer Prediger.
People may have antibodies for at least four months after they get COVID-19, a study
published Tuesday in the New England Journal of Medicine suggests.
The study pulled from a massive dataset from Iceland, looking for the presence of antibodies
in more than 30,000 blood samples. The samples came from three groups of people: those with
confirmed COVID-19 cases, those who had been exposed to the virus but weren't necessarily
infected, and those who had no known exposure.
The researchers focused on a small subset of 487 people who had had more than one antibody
test, which allowed researchers to see whether antibody levels remained stable or faded over
time. In this group, the researchers found, antibody levels increased in the first two months
after diagnosis and remained stable for the next two months.
Stefánsson said the study detected antibodies in a significant number of people who
had been asymptomatic and were never tested for COVID-19.
Not everyone developed antibodies after infection, the authors wrote, suggesting that some
people might have weaker immune responses to the virus. It's possible, however, that those
people had false positive diagnostic tests and were never sick in the first place.
The researchers noted several other interesting trends. Antibody levels were higher in older
patients and in those with more severe disease. Women also had lower antibody levels compared
to men, and smokers had lower antibody levels than nonsmokers.
"What they're seeing here is that they're inducing a pretty strong immune response," said
Jason Kindrachuk, an assistant professor of medical microbiology & infectious diseases at
the University of Manitoba in Winnipeg.
But while the data suggest that antibody levels remain stable for at least four months,
questions remain.
"What we don't know is really the million-dollar question: How do these antibodies reflect
immunity against this virus and inhibition of this virus," said Kindrachuk, who wasn't involved
with the research. "Just because you see antibodies being produced, it doesn't tell you that
those antibodies are going to act specifically against the virus."
In other words, it's unclear whether the antibodies will protect people from being
reinfected.
Confirmed cases of people being reinfected with the coronavirus are exceedingly rare. Last
week, it was reported that four people were reinfected, the only such instances out of more
than 25 million cases worldwide.
In August, the Centers for Disease Control and Prevention changed its quarantine guidelines,
saying people with confirmed COVID-19 didn't need to be tested again for three months if they
didn't develop any symptoms.
The study isn't the first to show that antibodies can stick around for some time after
infection.
The data in the new study are in line with those in a July preprint article showing that
antibody levels were stable for at least three months in patients who had recovered from the
virus in New York City, said Elitza Theel, director of the infectious diseases serology
laboratory at the Mayo Clinic in Rochester, Minnesota.
Study identifies six different "types" of COVID-19
A new study of COVID-19 , based on
data from a symptom tracker app, determined that there are six distinct "types" of the disease involving different clusters of symptoms.
The discovery could potentially open new possibilities for how doctors can better treat individual patients and predict what level
of hospital care they would need.
Researchers from
King's College London
studied data from approximately 1,600 U.K. and U.S. patients who regularly logged their symptoms in the COVID Symptom Tracker App
in March and April.
Typically, doctors will look for
key symptoms
such as cough, fever and
loss
of the sense of smell to detect COVID-19. The study, which has not been peer-reviewed, says the six different "types" of COVID-19
can vary by severity and come with their own set of symptoms.
"I think it's very, very interesting," Dr. Bob Lahita, who is not affiliated with the study, told CBSN anchors Vladimir Duthiers
and Anne-Marie Green. "Among the patients I see, those who recovered, many of them present different ways: some people with fever
and some without fever, and some with
nausea and vomiting, some people with diarrhea , etc."
The six clusters of symptoms outlined in the study are:
Flu-like with no fever: Headache, loss of smell, muscle pains, cough, sore throat, chest pain, no fever.
Flu-like with fever: Headache, loss of smell, cough, sore throat, hoarseness, fever, loss of appetite.
Gastrointestinal: Headache, loss of smell, loss of appetite, diarrhea, sore throat, chest pain, no cough.
Severe level one, fatigue: Headache, loss of smell, cough, fever, hoarseness, chest pain, fatigue.
Severe level two, confusion: Headache, loss of smell, loss of appetite, cough, fever, hoarseness, sore throat, chest
pain, fatigue, confusion, muscle pain.
Severe level three, abdominal and respiratory: Headache, loss of smell, loss of appetite, cough, fever, hoarseness,
sore throat, chest pain, fatigue, confusion, muscle pain, shortness of breath, diarrhea, abdominal pain.
The first level, "flu-like with no fever," is associated with headaches, loss of smell, muscle pains, cough, sore throat and chest
pain. Patients at this level have a 1.5% chance of needing breathing support such as oxygen or a ventilator.
The second type, "flu-like with fever," includes symptoms like loss of appetite, headache, loss of smell, cough, sore throat,
hoarseness and fever. Researchers say about 4.4% of patients at this level needed breathing support.
Patients with the third type, simply described as "gastrointestinal," do not have a cough as part of their illness. Instead, they
experience headache, diarrhea, loss of smell, loss of appetite, sore throat and chest pain, and about 3.3% needed breathing support.
Lahita referred to the following three clusters of COVID-19 as the "really severe types."
In type four, or "severe level one," patients experience fatigue along with headache, loss of smell, cough, fever, hoarseness
and chest pain. Patients at this level needed breathing support at a rate of 8.6%.
Type five, "severe level two," includes the symptoms of type four along with loss of appetite, sore throat and muscle pain, and
is mainly distinguished by
confusion
.
"That means you don't know where you are or where you live, whether you are in or out of the hospital, who your relatives are,"
Lahita explained. "That is very scary." Almost 10% of patients at that level need breathing support.
The most severe type of COVID-19 is referred to as "severe level three, abdominal and respiratory," and has all the above symptoms
along with abdominal pain, shortness of breath and diarrhea. Nearly 20% of these patients need breathing support.
"Those are the severe level threes who wind up on a ventilator, and then it is touch-and-go as to whether they survive the
infection entirely," Lahita said.
The U.K. researchers also found that only 16% of patients with type one COVID-19 required hospitalization, compared with nearly
half of the patients with type six.
Patients in the severe clusters also tended to be older or with pre-existing conditions and weakened immune systems, compared
to those in the first three.
Scientists hope the discovery, once further studied, could help predict what types of care patients with COVID-19 might need,
and give doctors the ability to predict which patients would fall into which category.
"I'm very happy that these six types have been identified and can give us an idea of a prognosis going forward for patients who
are afflicted with this virus," Lahita said.
"The current work suggests that while the G614 variant may be more infectious, it is not
more pathogenic. There is a hope that as SARS-CoV-2 infection spreads, the virus might become
less pathogenic,"
WHO now says asymptomatic spread of coronavirus is 'very rare'
Jun. 09, 2020 - 4:06 - World Health Organization changes its tune on asymptomatic patients
spreading COVID-19; reaction from Fox News medical contributor Dr. Marc Siegel.
Although numerous studies have suggested people can spread the virus before they show
symptoms, the WHO has largely dismissed those as anecdotal or pointed out that they were
based on modelling.
Babak Javid, an infectious diseases doctor at Cambridge University Hospital, says many
scientists are persuaded by the studies published so far and think WHO should publish the
data it is citing to explain why it believes transmission of the disease in people without
symptoms is "rare".
"If you're going to make a really important statement like that, it would be good to
back it up," Javid said. "I think WHO is an important organisation, but they've made a lot
of statements that have been misleading."
What does an anti-body test do? I just had one last week and awaiting the results - was a
cruise passenger and international air passenger during the month of January in a later
suspected area. (not Asia).
Here is why I did the anti-body test: (Quest Labs - fee service, no RX- 99% accuracy -
drawn blood vial test)
1. Helps substantiate dates and areas of transmission that may not yet be in the data
pool.
2. Tracks the rates of asymptomatic or mildly symptomatic cases occurring among the
"elderly", in order to see if there is an enhanced risk of not in this age group, if there
are no underlying co-morbidities.
3. Adds demographic data specific for the travel industry.
4. Allows possible donation of anti-body serum for research and perhaps mitigation of
those who are affected.
5. Personal peace of mind -been there and done that. Freedom to move about.
6. Provides baseline for duration of immunity; resilience of immunity or data showing
re-infection can be possible.
Primarily it is for data gathering to help stop the hysteria. That was worth the time,
money and blood donation for me. We will never know the true extent of this virus, its
impacts, its initial modeling accuracy until we start plugging facts into the "expert"
hypotheticals.
Taking one for the team is the way I see it. Will I now become a local Typhoid Mary and
our house burned down if this data becomes known? Or will people stop walking out into the
roadway in faux deference to my advanced age as I pass by, from our deliciously virtue
signaling "progressive" population in blue state California.
"Provides baseline for duration of immunity; resilience of immunity or data showing
re-infection can be possible. Primarily it is for data gathering to help stop the hysteria."
Yes
The Last but not LeastTechnology is dominated by
two types of people: those who understand what they do not manage and those who manage what they do not understand ~Archibald Putt.
Ph.D
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