By Glenn Ellis
Late last month, the American Medical Association issued the following statement: “No therapies have yet to conclusively show effectiveness against COVID-19”.
According to information on the Centers for Disease and Control Prevention (CDC) website, “Two kinds of tests are available for COVID-19: viral tests and antibody tests. A viral test tells you if you have a current infection. An antibody test tells you if you had a previous infection.
Antibodies are produced by a person’s immune system, and these antibodies are critical for control and clearance of the virus. An antibody test may not be able to show if you have a current infection, because it can take one-three weeks after infection to make antibodies. 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.
With so much still unknown about immunity to COVID-19 and dozens and dozens of antibody tests that have not been rigorously validated, experts worry that widespread antibody screening may give those who test positive a false sense of security.
The whole idea of antibody testing goes back to around the time of the influenza pandemic in 1918. Medical experts at the time thought that you could take serum (or plasma) from people who have had the infectious disease and have recovered. You then take their antibodies and inject them into someone who is having a severe case, or rapidly deteriorating, and protect them. Sounds reasonable.
With other diseases, the presence of antibodies often means you have acquired immunity against re-infection, for at least some period of time, but that is not known yet in the case of COVID-19. That means that a positive antibody test doesn’t guarantee immunity. It has not been proven that the antibodies that are being produced are in fact neutralizing antibodies. It’s possible that an antibody may bind to a part of the virus that the virus doesn’t need to infect our cells. In order to be neutralizing, an antibody must prevent the virus from infecting our cells.
Just recently, the Federal Drug Administration (FDA) cracked down on the nearly 200 commercial antibody tests that have hit the market, citing that some test kits are fraudulent and show inaccurate results. An accurate antibody test would help the scientists and researchers gather the data on who has gotten the virus, including those who’ve showed no symptoms of being sick.
It could even help develop a treatment to fight the virus. But experts warn that they have not been able to determine if someone is immune once they’ve had it. We now know from all of this that a positive antibody test may not necessarily mean you’re safe from ever getting the virus again.
Swab testing, despite being the “gold standard’ for COVID-19 testing has its own drawbacks. The sample needs to be collected carefully from the correct area. It’s estimated that errors can occur about 8 to 10 percent of the time, which contributes to false negatives. Labs also need specialized equipment and skilled staff. Lab officials say the amount of virus in the upper respiratory tract seems to peak in the first week of symptoms and could fall too low to be detected later.
Another thing about the swab test. It doesn’t end with just getting tested. Let me remind you that knowing if you are infected with the virus starts a whole series of questions for you and your healthcare team. If you are positive, decisions have to be made (sometimes, this can be without your agreement). Do you need to be hospitalized and separated from other patients? If you can go home, how should you isolate yourself?
Many people are anxious to get tested so that they can get back to their normal lives. Just know that there is a strong possibility, based the way this virus is spreading, that you might come up with a positive result. You should be prepared for the results; no matter what they conclude.
According to the COVID Tracking Project, only about 8.4 million Americans, or 2.5 percent of the total U.S. population, were tested for COVID-19 as of May 9. This reflects, to a large degree, the strain the demand for testing has placed on manufacturers and labs. Some diagnostic test suppliers have deliberately stopped testing for certain diseases, for example, to enable them to allocate more resources to manufacturing and supplying COVID-19 tests.
COIVD-19 has forced us all to have to consider things that we never imagined. But it is for our benefit that we get good information to inform our decisions.
One last word about the “reopening of the country”. My friend, Rev. John E. King, Jr., told me that there are three types of people: one-third can’t wait to get back out there; another third of the people are waiting to see what happens to the first third before going back out; and the last third are those who don’t care what happens to the first or second third, they ain’t going back out there! Which third are you?
We need to know that testing is not the be all, end all, that we think they are. Some scientists believe that tests for the coronavirus are only about 70 percent accurate. A false negative is problematic because it tells the patient they don’t have the virus.
Glenn Ellis, is a Harvard Medical School Research Bioethics Fellow and author of Which Doctor?, and Information is the Best Medicine. For more good health information visit: www.glennellis.com
