In the urgent efforts to stop the spread of COVID-19, there has been a lot of talk about antibody testing. But what is it, and can it help put an end to this pandemic?
Antibodies are proteins in the blood that fight infection related to a specific disease and usually provide protection against getting that disease again. Some have suggested that by testing the blood for COVID-19 antibodies (not to be confused with the nasal swab diagnostic tests, which are screening for the presence of the active virus in one's body), we could identify individuals who have had the coronavirus and may now be immune (safe from being reinfected). This would help identify people who had no symptoms but may have been infected with the virus, or people who did experience symptoms but never got tested for COVID-19 and treated their mild symptoms at home. Further, having this information would help us return to a more normal, less restrictive way of living and working.
According to Courtland Keteyian, M.D., who leads population health efforts (work to reduce certain key health issues and improve outcomes among the population) at Henry Ford Allegiance Health, there are several problems with this theory.
“First, we do not have sufficient evidence to know that a person who has survived COVID-19 cannot be reinfected. Even if that were true, we do not know how long this immunity would last,” Dr. Keteyian says. “Second, there are numerous antibody tests that were approved through an FDA expedited pathway. The accuracy of most of these tests is still an open question. For instance, the test might identify antibodies to one of the many other kinds of coronaviruses by mistake.” He further explains that antibodies for some diseases, like HIV, can be present in the blood and not protect against infection.
Timing is also an issue, because antibodies are typically not detectable until one-to-three weeks after the first symptoms of the virus. So the test might not find antibodies in someone who is currently infected with COVID-19.
For these reasons, antibody testing is not a viable way to drop COVID-19 restrictions faster -- at least not yet. Scientists and experts continue to study this disease and work on developing more reliable tests.
“We must still rely on screening and nasal testing results, practice social distancing, wear face masks in public and wash hands frequently. Remember that following these measures is the reason the Michigan COVID-19 risk has improved,” says Dr. Keteyian.