FDA authorizes new T-cell test that could be game changer for COVID-19 long haulers.
While current antibody tests aim to provide similar evidence, accuracy varies.
Some studies have shown antibodies wane after a few months' time, so, while antibodies can indicate whether a person's had the coronavirus in the past, timing is key: Test too early and the antibodies may not yet be detected, but test too late and the antibodies may have already faded from the blood stream.
While researchers still don't know exactly how long after a COVID-19 infection the T-cell immune response remains active, the longevity of the cells' "memory" makes for a promising candidate in the forensic work of tracking past infections. "So many people had the disease, recovered, never got a clear-cut diagnosis, yet they're suffering from these bizarre, persisting symptoms," Li added. "The T-cell test has been really useful in this long tail of COVID to help patients establish where they are."
The test is administered via blood draw. T-cell DNA is then extracted and sequenced with Microsoft's artificial intelligence, mapping out the immune system's "massive black box" data into navigable science, researchers say.
1 Tay MZ, et al. The trinity of COVID-19: immunity, inflammation and intervention. Nat Rev Immunol. 2020.
2 Ng O, et al. Memory T cell responses targeting the SARS coronavirus persist up to 11 years post-infection. Vaccine. 2016.
3 Zuo J, et al. Robust SARS-CoV-2-specific T-cell immunity is maintained at 6 months following primary infection. bioRxiv. 2020.
4 Channappanavar R, et al. Virus-specific memory CD8 T cells provide substantial protection from lethal severe acute respiratory syndrome coronavirus infection. J Virol. 2014.
5 Dalai S, et al. Clinical Validation of a Novel T-Cell Receptor Sequencing Assay for Identification of Recent or Prior SARS-CoV-2 Infection. medRxiv. 2020.
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