Maryland doctors have started testing for the presence of COVID-19 antibodies in patients' blood samples, but many of the results are coming back negative.
Lindsey Ellison was sick in December, an extreme cough-headache-energy-zapping kind of sick.
By the time she recovered in January, news of the coronavirus began spreading. But she didn’t suspect she was infected with it until she heard from a colleague who had been to Wuhan, China, the pandemic epicenter, and also later gotten sick.
“I thought, whoa, we had the exact same symptoms,” said Ellison, a life coach from Annapolis. “And they seem like COVID-19 symptoms.”
It was too late to diagnose what sickened her, but on May 8, she became one of the first people to get an antibody test at her doctor’s office, Evolve Direct Primary Care in Annapolis. She’s now among a growing band of people seeking such tests to find out whether they ever had the disease caused by the coronavirus — even though many tests aren’t yet government approved and there are questions about whether they’re effective and even what they mean with this virus.
Such antibody tests, also called serology tests, are usually performed a couple of weeks after recovery because it takes time for the body to produce antibodies, which are specific proteins the body makes in response to infections. Research suggests they may ward off new infections in the same way as a vaccine.
The tests are being sought by people who want to confirm their suspicions or feel a little more protected from the virus that has killed almost 85,000 people in the United States and infected more than 4.4 million worldwide. Public health officials also want to use the tests to better understand the infection rate for a disease that doesn’t always produce obvious symptoms.
For now, experts and government agencies, as well as Ellison’s doctor, warn that many tests now available are not reliable and no one yet knows if having COVID-19 makes people immune to reinfection or for how long.
“There is a lot of variability in antibody tests,” said Dr. Karen Kotloff, an infectious disease expert at the University of Maryland School of Medicine. “People racing to try and get a test should understand.”
Some tests used by researchers are helping show infection rates in some places, she said. But dozens of tests have been rolled out to the public without proof they work. And even if they do give accurate results, they only test for the presence of antibodies and don’t show if those antibodies “neutralize the virus.”
Kotloff said scientists believe antibodies do offer some immunity, based on past research on other coronaviruses, including SARS, MERS and the common cold. But there’s not enough proof. When there is, she said the tests will provide valuable information, particularly for health care workers and others most at risk for complications, and then for people who want to return to more normal lives.
The U.S. Food and Drug Administration regulates both antibody tests and the diagnostic tests that show if someone is currently infected. The agency initially allowed dozens of antibody tests to flood the market without review, but has since sought evidence from manufacturers and last week said about 12 tests have “emergency use authorization” and can be used as further evidence is gathered.
Ellison’s doctor at Evolve, Dr. Michael Freedman, said he held off offering a test until he felt more confident in the results. He started offering tests in recent days, and demand has been brisk. Ellison was among the first, and she tested negative.
Freedman believes she may have had COVID-19, but the test didn’t pick up antibodies four months later or she never produced enough to register.
Patients are not charged for the tests, but he said he’s making them available because he sees public health value in widespread testing. He also sees psychological value in offering the tests because people feel like they “made it through the firing range” if they test positive and feel less scared, even if they can’t abandon precautions just yet.
Freedman said he’s limited the tests, done by appointment only, because patients need to come into the office for a blood draw. He’s not yet had to call anyone with a positive result, but he said he would tell them to continue distancing from others, wearing masks in public and taking all other recommended steps.
“We don’t want anyone getting a false sense of security,” he said. “But testing can be an important tool for public health ... And there definitely are psychological benefits for patients just in knowing that the cough they had in February was or wasn’t COVID-19.”
Evolve sends samples to Quest Diagnostics, one of the nation’s largest lab companies, which uses a test approved by the FDA for emergency use. Quest reported that in just over three weeks, it had performed 620,000 antibody tests nationwide and could now perform 200,000 such tests a day, with results in one to two days. That’s four times more than the number of diagnostic tests it can perform, though that number is expected to double by next month.
Still, warnings about the tests from public health agencies abound, including from the World Health Organization and the U.S. Centers for Disease Control and Prevention.
The CDC says it is evaluating the performance of commercially available tests. In the meantime, it said some may produce false negative results because some people still have infections, take longer than three weeks to produce antibodies or may not produce antibodies at all.
And, the CDC warns on its website: “We do not know yet if having antibodies to the virus can protect someone from getting infected with the virus again, or how long that protection might last."
An April report from the Johns Hopkins Center for Health Security echoed the CDC’s concerns.
“Given the inaccuracies in available tests and the uncertainty about how the test results correlate to immunity, this is not a justifiable step at this time,” the report says.
Ellison said she understood the test’s limitation but had wanted to test positive because she strongly believed she could aid public health officials, who could have traced her steps and understood more about the path of infections. She would have been among the first cases in the United States.
She also wanted to help medical workers by donating plasma or volunteering in other ways.
Ellison thought she was infected in New York during a speaking engagement and could have spread the virus while in New Orleans where she went with friends for New Year’s Eve and Maryland where she lives with her husband and two sons. New York and New Orleans went on to become hot spots for infections.
There also was the potential comfort in knowing whether she’d had the disease and survived and might not be able to get it again.
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“I was surprised to learn I was negative, and a little bummed,” she said. “I think fear is propelling this virus, and that’s because of all the unknowns. I think we’ll see a lot of other disease spreading from this, mental health disease, alcoholism, suicide. I’m a counselor and my emails has been buzzing nonstop.”
She said if there is another test offered to her at some point, she will take it.
Those tests might be on the horizon, but for now available tests remain of limited use, said Dr. Leana Wen, former Baltimore City health commissioner and a professor at George Washington University School of Medicine and Health Sciences.
“They can be useful to figure out exposure and understand infection rates, but I would not use them to guide individual decision-making,” she said of existing tests. “We don’t know whether having the antibody confers immunity, and we don’t know whether immunity means you are protected from COVID-19. I wouldn’t want people to get false reassurance if they have a positive antibody test.”