Are T-Cell Tests the Key to Monitoring COVID Immunity?

Although safe, effective vaccines have provided us with some COVID-19 immunity, there are still questions about how protected we are, and how long we’re protected.

Antibodies, whether from a COVID vaccine or from COVID itself, don’t last very long. And even if they did, antibody testing hasn’t exactly caught on the way rapid antigen testing has, so most people don’t now if they have antibodies.

Now, a recent paper published in Nature Biotechnology has looked at how a scalable T-cell test could change our understanding of our bodies’ defenses in real time.

T-Cells vs. Antibodies

T-cells and B-cells are types of immune cells called lymphocytes. Think of them as a one-two punch of the adaptive immune system.

When a virus enters the body, B-cells produce antibodies that can bind to antigens and attack a virus. Then, T-cells destroy the cells that have been infected, which also gets rid of the invading virus.

B-cells and T-cells also have long memories. Antibodies can diminish fairly quickly, but when B-cells and T-cells recognize a virus, they immediately leap into action and ramp up antibody production to fight it off.

Can T-Cell Testing Go Mainstream?

Antibody tests are cost-effective and widely available, but they only measure the antibody response and give an incomplete view of the body’s capability to fend off an attack by a known virus.

T-cell testing is expensive and not something you can do on your own at home. Currently, there is one T-cell test (T-Detect) available in the United States but it requires a blood sample taken by a phlebotomist at a lab.

In a recent study funded by Hyris (a biotech company developing the rapid T-cell test), researchers found a way to lower the cost and labor involved in T-cell testing.

In simple terms, the researchers mixed a blood sample with SARS-CoV-2 cells to measure the T-cell response. It took less than 24 hours to complete the test, which the researchers found gave a more accurate picture of a person’s true immunity.

George Jour, MD, an advisory board member and a clinical consultant at Innovative Health Diagnostics who was not involved in the study, told Verywell that the simplified workflow presented by the researchers could be groundbreaking as it has the potential for use on a wide scale.

“When you scale something like this to the masses, you want it to be cheap and accessible,” said Jour. “They simplified the workflow to a point where they use tools that even small labs have.”

However, Jour cautioned that while the test might be scalable and affordable, it has yet to be approved by the Food and Drug Administration (FDA) or Clinical Laboratory Improvement Amendments (CLIA). Until that happens, the test won’t be available.

Who Needs T-Cell Tests?

If the approval hurdle is cleared, the T-cell test and its results could be valuable to people for people who are more susceptible to infection.

For example, the test could be useful for immunocompromised people who might not be producing enough antibodies to vaccination or people who are recovering (convalescent).

Phil Felgner, PhD, a professor of physiology and biophysics at the University of California at Irvine, told Verywell that throughout the pandemic, he had many immunocompromised people ask him for immunity testing in hopes of being able to live less cautiously or give their results to their provider to justify a booster.

“Physicians were stuck because people were coming in and asking for boosters, and they wanted more information before advising people,” said Felgner. “They had no advice or protocol to follow other than the CDC guidelines, but the CDC guidelines are not personalized medicine. It’s making decisions for an entire population.”

Felgner said that as community COVID infection reporting winds down, people will need to start taking responsibility for knowing their immunity.

Jour agreed, adding that it will be more of an “individual effort until the platform becomes more popular and usable across different small labs.”

Still, Jour said that will “create momentum for the local authorities to create clear recommendations about who the candidates are that would benefit from this particular T-cell activation test.”

Felgner said that COVID is just the first application for these tests, as many other diseases could benefit from rapid T-cell testing. In the future, it could even lead to the creation of a wider swath of personalized medical recommendations.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.