Lawmakers push for COVID-19 antibody tests to restart economy as health experts caution limitations

Matt Drever, left, scrapes bacteria from an agar plate during an antibody phage experiment as Charlie Holst watches at the Pfizer laboratory at the the University of California at San Francisco (UCSF) Mission Bay campus. Pfizer Inc., Astra Zeneca PLC and Eli Lilly and Co. are among the major international drug companies signing seven-figure, multiyear umbrella agreements with schools such as New York University, Harvard and the University of California-San Francisco. The deals cover a range of research projects and offer campus scientists access to once-proprietary experimental drug compounds owned by the corporate labs.

Chairmen of the two Senate committees responsible for health policy and spending are pushing for more access to COVID-19 antibody tests, saying they will help save lives and restart the economy sooner by determining who is - at least temporarily - immune to the disease.

In a letter sent last week, U.S. Sens. Lamar Alexander, R-Tenn., and Roy Blunt, R-Mo., urged Health and Human Services Secretary Alex Azar to clarify that the recently enacted $2.2 trillion CARES Act - which grants Americans free tests to determine whether they currently have COVID-19 - also allows for a free antibody test to detect immune response to past infection.

"We are dealing not just with a medical issue here," the senators said in a news release. "We are dealing with an issue of confidence. For weeks, Americans have watched 24/7 news coverage of the dangers of COVID-19. Even if the government says you can go back to work and back to school, many Americans may be reluctant to leave their homes."

Over the weekend, the U.S. Centers for Medicare and Medicaid Services confirmed that the new law covers antibody tests as well and services associated with the test, such as a doctor's visit, at no cost for Americans with private health insurance.

Experts agree that more availability of both rapid diagnostic and antibody tests are important, but so is understanding their differences and potential downsides.

The main test for diagnosing current infection with the novel coronavirus is a molecular test that usually uses a nasal swab to detect the virus itself. It can have various turnaround times, typically ranging from 24 hours to several days, depending on if the laboratory is far away, overwhelmed or out of needed supplies.

"Rapid" versions of these molecular nasal swab tests that can be completed at the point of care, such as the Abbott-ID test, are starting to become available.

There are also new rapid antibody tests that use a finger prick to sample blood - called serology or serum tests - for people who have recovered from COVID-19, such as the one Alexander and Blunt are touting. These tests are typically not used to diagnose active infections.

Dr. David Aronoff, chairman of the department of infectious diseases at Vanderbilt University Medical Center, said antibody tests will help offer more information about how many people in the population have been infected, including people whose symptoms were mild and they never sought medical care, or people who didn't even know they were infected.

"The benefit of identifying those antibodies is that it strongly suggests that a person has been infected with the coronavirus," Aronoff said. "We are assuming that our immunity after we get infected protects us against getting infected again, which right now we think it is the case.

"The more people we can test both for the actual virus and for immune response, it's going to ultimately let us know when this pandemic is waning and when we can start to get people back to business," he said.

It's unclear the level of immunity a person has after recovering from the virus. Last Wednesday, Dr. Anthony Fauci, director of the National Institute for Allergy and Infectious Diseases, told the Journal of the American Medical Association that it's reasonable to assume people will have antibodies in their system until September or October.

Because the molecular tests require special machines and supplies to run, Aronoff said he thinks that rapid antibody blood tests will become increasingly popular.

The point-of-care rapid antibody blood tests behave similar to pregnancy tests, but instead of urine, a provider places a drop of blood on a strip of paper allowing the blood to flow across. If there are antibodies in the blood, they will create visual lines to indicate the presence of antibodies. Those tests take about 15 minutes, and the answer is qualitative, meaning you get a yes or no answer.

"The trade off is that they're faster, and they can be done at the point of care, and they're less expensive," Aronoff said. "The issue is that these tests are coming out so quickly that it's not yet been possible to see really good studies to show that their performance is really specific and very sensitive.

The Food and Drug Administration granted its first emergency authorization for a rapid antibody blood test to the company Cellex. The World Health Organization recommends that the test only be used in research, and Cellex recommends the test be used in conjunction with the molecular nasal swab test.

Aronoff said there's reason to be cautious about rapid antibody tests, because it's possible that they produce false negative results - meaning that the test says someone wasn't previously infected when in fact they were - or false positive results - meaning the test says a person was infected, but they weren't. False positives are more concerning, he said, because they could reassure somebody that they now have immunity when in fact they don't.

The various tests can also be confusing, he said.

"If someone is symptomatic and is worried that they have COVID-19, currently the best test we have is the molecular detection of the virus itself in the nasal passage," Aronoff said. "Antibody tests take a little bit of time to develop, so you could be quite symptomatic with COVID and have a negative antibody test for sure. So it's important for people to know that."

Chattanooga resident Veronda Siever shares these concerns after recently receiving a blood serum test at her primary care provider. Siever went because she was having trouble breathing and had felt sick for about five days.

The test was negative, but Siever began to do some more research and called the health department hotline. Because she has symptoms, she now believes she was given the wrong test.

"People say they like that [antibody] test better, but the health department told me that when you're actually sick, it's not going to work for you," Siever said as she took labored breaths. "I'm not even sure it was the right antibody test, because of the way the health department reacted, there aren't a lot out there."

She's since gone to the Hamilton County Health Department's drive-thru testing site and is awaiting results.

"I was angry to begin with, but then I thought there's no reason to be angry. I just don't want it to happen to anyone else," Siever said. "It can give people false security, false readiness, and they can think they're not infected and be going to work. I don't want anybody to walk around being sick and thinking they're OK."

Contact Elizabeth Fite at efite@ or 423-757-6673.