New COVID-19 tests that can tell not only whether you have had coronavirus before, but estimate how many antibodies to the virus are present in the body, have been given authorization by the US FDA. The latest iteration of so-called serological tests, the two new diagnostics aren’t designed to identify whether a patient is currently infected by COVID-19, but instead could be essential in figuring out whether having had coronavirus then grants an individual immunity against it in future.
Testing for COVID-19 has been controversial since the onset of the pandemic. In addition to concerns over access to testing – which remains a divisive topic, particularly in the US, where getting a coronavirus test can still be difficult or unduly expensive – there are also several types of test which can be carried out.
PCR or antigen tests are used to figure out whether an individual is currently infected by COVID-19. However they don’t show whether a person has been infected in the past, but since recovered. For that, serological tests have been used; the flip side is that since they rely on the presence of antibodies produced by the immune system as a result of an infection, they are for retrospective assessment of whether coronavirus was present.
Now, the US Food and Drug Administration has authorized two new types of serology tests, which display an estimate of the quantity of antibodies in an individual’s blood, rather than simply confirm the presence of those antibodies. ADVIA Centaur COV2G and Atellica IM COV2G can indicate the quantities of antibodies produced against the COVID-19 virus.
“Being able to measure a patient’s relative level of antibodies in response to a previous SARS-CoV-2 infection may be useful as we continue to learn more about the virus and what the existence of antibodies may mean,” Tim Stenzel, M.D., Ph.D., director of the Office of In Vitro Diagnostics and Radiological Health in the FDA’s Center for Devices and Radiological Health, explained of the newly-authorized diagnostics. “There are still many unknowns about what the presence of SARS-CoV-2 antibodies may tell us about potential immunity, but today’s authorizations give us additional tools to evaluate those antibodies as we continue to research and study this virus.”
One of the confounding factors in developing treatment and management strategies for COVID-19 is understanding just how antibody reactions operate. For example, it’s unclear just how long those antibodies actually persist in the body after an infection. Even if they do stick around, scientists aren’t certain whether they can prevent reinfection in future.
As a result, just having antibodies present shouldn’t be taken as proof that you can’t catch COVID-19 again – or, indeed, that you should lessen your commitment to social-distancing, mask wearing, and other strategies designed to reduce the virus’ spread.
“Patients should not interpret results as telling them they are immune,” Dr Stenzel cautions, “or have any level of immunity, from the virus.” The FDA says that, while antibodies for coronavirus may be identified, that doesn’t mean an individual is safe to go back to work, either. The US CDC changed its guidelines on COVID-19 quarantine and returning to work in late July.