US regulators gave emergency authorization to a fourth test for coronavirus antibodies in an effort to help health authorities identify who has already been infected and may have developed immunity to the virus on Wednesday.
Mt Sinai Health System, in New York, was the first lab in the US to announce it had developed such a test, in March.
The newest serologic test can detect antibodies the body produces in response to coronavirus as early as three days after a patient develops symptoms.
As antibody tests are rolled out, the US should gain a clearer picture of who has had the infection and may be able to return to work with minimal risk of reinfection. New York Andrew Cuomo said last week he wants to test young, healthy people who may have already had and cleared the infection, and send them back to work.
Already, the scientists at Mt Sinai have distribute the protocol for their test to more than 200 labs in the US and abroad.
However, the US Food and Drug Administration’s (FDA) authorization explicitly said that analysis of the test must be confined to Mt Sinai’s lab.
Mt Sinai Health Systems received FDA authorization for its test for coronavirus antibodies on Wednesday, a vote of confidence in the test’s accuracy at detecing who may have already been infected with the virus and developed immunity (file)
FDA officials have already authorized tests made by Chembio Diagnostics, Ortho Clinical Diagnostics and Cellex.
Diagnostics giant Abbott Laboratories also released an antibody test, which it can distribute under relaxed FDA guidelines. New York state has already begun antibody testing using a test developed by its own Wadsworth Lab as well.
Serologic, or blood antibody, tests are notoriously difficult to make, largely because there are many components of a virus that could be responsible for triggering the immune response.
But research on the virus that causes COVID-19 – SARS-CoV-2 – has largely focused on the ‘spike’ protein on its surface that allows the virus to attack respiratory cells.
Like most labs, the Mt Sinai team quickly narrowed their work to making a test for antibodies that form in reaction to this protein.
They found that this spike is quickly recognized as an invader and the human body wastes no time in ramping up production of antibodies to fight the infection.
Experiments found that the test the team developed was both highly specific and highly sensitive, meaning that it’s unlikely to cross-react with any other viruses or pathogens, and rarely missed someone who had tested positive for coronavirus and should have antibodies.
‘Our test can pick up the body’s response to infection, in some cases as early as three days post-symptom onset, and is highly specific and sensitive,’ said Dr Florian Krammer, who led the research team.
‘We have shared the toolkit needed to set up the test with more than 200 research laboratories worldwide to help mitigate this global crisis
Dr Krammer and his team began working on their coronavirus blood test in January, before the pandemic had even hit the US.
When it was completed in March, the researchers said they would begin using it in very limited settings, primarily to test workers in its own clinics.
Diagnostic testing for coronavirus has stumbled into existence in the US, and is only just becoming widely available across the country where the expansion of tests means thousands of additional cases are being identified a day bringing the US total to over 42,000.
Cheaper, faster, more reliable serologic tests will serve a different function, however: they indicate who has already been infected with coronavirus, whether they knew it or not, and has developed antibodies to fight the infection.
People whose blood tests positive for coronavirus antibodies are unlikely to be re-infected and may be able to return to work, helping to restart the the US’s largely paused economy.
Mt Sinai is authorized to begin running the antibody tests at its lab in New York City. More than 222,000 people in the state have tested positive – but the antibody test will likely reveal far more who have already had and cleared tine infection without knowing it
And when enough people’s blood tests positive for these antibodies, it will signal to health officials that restrictions on movement, business and social contact can be relaxed without risking a steep uptick in the virus’s spread.
One of the greatest challenges to containing and understanding the coronavirus epidemic is the mystery number of people who may be unwittingly infected.
If COVID-19 behaves similarly in the US to the way it has isn China, more than 80 percent of patients will have only mild symptoms easily mistaken for the common cold or flu: fever, coughing and body aches.
One study conducted at Huazhong Unversity of Science and Technology in Wuhan, China – the origin and epicenter of the outbreak – estimated that at least 59 percent of infected individuals had o idea they were sick, didn’t get tested and were roaming the city, exposing others to the virus.
About 18 percent of the infected passengers on the infamous Diamond Princess cruise ship never developed even mild symptoms of the virus, according to a study conducted by Dr Gerardo Chowell, a mathematical epidemiologist at Georgia State University.
By now, it’s quite clear that people with more symptoms of COVID-19 are also more contagious.
Drive-thru testing sites have cropped up across the US, including in California (pictured), but the serologic test will serve a different function. It will go first to health care workers to find out if they’ve been infected already and developed an immune defense against the virus
Once someone is suspected of having coronavirus, their blood is regularly drawn, and these samples can be analyzed with the serologic test and it can show if they were infected ‘a month ‘ before , the Mt Sinai team said
But they’re also far easier to identify and contain.
It’s silent spreaders and the uncertainty of who might be infected that makes coronavirus dangerous and makes sweeping restrictions on activity necessary.
Since the early days of the pandemic – before officials would call it a ‘pandemic’ the World Health Organization has repeated that a serologic test will be key to painting a clearer pictured of how much of the population is really infected, and how serious coronavirus really is for most.
Now, the US, which has struggled so much to deploy swab diagnostic tests, is finally beginning to roll out long-awaited antibody testing.
Mt Sinai uploaded step-by-step instructions for its test last month, to be used by other hospitals and research labs, Dr Florian Krammer, head of the microbiology labethat created the blood test told Leapsmag.
Dr Krammer told Leapsmag that patients suspected of having coronavirus have their blood drawn regularly, and these samples can be analzyed with the serologic test without doing a new blood draw.
The serologic test can also detect antibodies in someone who is not currently sick, but had been a month previous.
And if these people, or those currently infected, have high enough levels of these antibodies, they may be protected against the virus going forward.
‘People probably cannot get reinfected once they mount a good immune response and have antibody levels,’ Dr Krammer told Leapsmag.
Once that is the case, these people are more likely safe to resume relatively normal activities, without risk of becoming infected or infecting someone else (if they’ve tested negative for the virus itself).
It’s still too soon to tell, however, how long this immunity will last.
‘If a sizeable portion of a local community has some protection, authorities can be more confident in relying less on invasive measures,’ wrote former FDA Commissioner Scott Gottlieb in a Wall Street Journal opinion piece.
‘Once deployed, serological tests are cheap, straightforward, and easy to scale.’
But the test won’t be for everyone – at least not at first.
‘It will be essential workers who need to be tested first, like nurses, firefighters, and doctors,’ said Dr Krammer.
‘It will be great to know that they would not put themselves or others at risk by going back to work because they cannot spread the disease.’