New York scientists have created the first blood test to detect whether someone has already been infected by and developed immunity to coronavirus.
Researchers at Mt Sinai’s Icahn School of Medicine have made the first so-called serologic test for COVID-19 in the US, and they plan to roll it out in the next few days in its 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.
It comes as 100 coronavirus deaths were reported in the US in a single day for the first time since the virus began infecting Americans.
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.
Mt Sinai scientists have developed a serologic test for coronavirus that can detect when someone has developed antibodies after being infected with the virus,
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.
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.
Already, these tests have been developed by China, Singapore and South Korea and the Centers for Disease Control and Prevention (CDC) has developed and is verifying their test.
Now, the US, which has struggled so much to deploy swab diagnostic tests, finally has a blood test for antibodies against coronavirus, according to a preprint published by the Mt Sinai team last week.
Mt Sinai uploaded step-by-step instructions for its test on Monday, to be used by other hospitals and research labs, Dr Florian Krammer, head of the microbiology labe that created the blood test told Leapsmag.
These antibodies should be detectable after about seven days of infection.
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.
Once a significant proportion of the US has developed good immunity against the virus, measured by the blood test, it may be safe to lift restrictions like the lockdowns in at least 12 states across the US
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 sizable 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.’
Dr Krammer and his team don’t yet know how widely the serologic test will be available, but they have widely distributed the instructions for the testing protocol, but their clinics will begin using it this week.