HWN Suggests

The Value of Measuring T-Cell Response in COVID-19

The role T-cells have played in understanding COVID-19 immunity and vaccine response has been limited at best. Measuring T-cell response could help provide a more complete picture of protection after vaccination. A growing body of evidence indicates T-cells may be an important correlate for protection and should be considered as an endpoint for vaccine clinical trials and in the development of next generation vaccines and boosters.

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Articles of Interest

COVID-19 testing turns to T cells

The test is not intended for the diagnosis of active infection but is a complement to antibody tests used to confirm recent or previous infections.

FDA authorizes new test, built with machine learning, to detect past Covid-19 infections

Unlike tests that detect bits of SARS-CoV-2 or antibodies to it, the new test, called T-Detect COVID, looks for signals of past infections in the body’s adaptive immune system — in particular, the T cells that help the body remember what its viral enemies look like. Developed by Seattle-based Adaptive Biotechnologies, it is the first test of its kind.

New Type of Test May Better Discern Immunity to the Coronavirus

The test may also offer insights into Covid-19. And about 5 percent of patients who are severely ill show a “tremendous drop” in their T cell response, Dr. Baldo said. But in a vast majority of people, the T cell response seems to peak around Day 10 and persists for many months, he said, adding: “We’re seeing an earlier, a more robust and even a more durable T cell response as opposed to the antibody response.”

Which is Superior, COVID-19 Antibody Testing, or T-Cell Testing?

While there has been much interest in T-cell testing for past COVID-19 infections, side-by-side testing for T-cells and COVID-19 “neutralizing” antibodies such as the Spike (S-RBD protein) antibody clearly demonstrates the superiority of antibody testing, especially in milder or asymptomatic COVID-19 infections where T-cell responses are more variable. In addition, some T-cells show high rates of cross-reactivity with non-COVID-19 viruses. T-cell assessments cannot determine whether or not protective “neutralizing” antibodies are being produced.

Resources

T-Spot Covid

The T-SPOT.COVID test is a standardised ELISPOT based technique for qualitative detection of a cell mediated (T cell) immune response to SARS-CoV-2 in human whole blood, intended for use as an aid in identifying and monitoring individuals with a T cell immune response to COVID-19 vaccination or SARS-CoV-2 infection

T-Detect Covid

T-Detect COVID correctly confirmed recent or prior COVID-19 infections 97.1% of the time from date of RT-PCR diagnosis with 100% specificity