Scientists around the world have been dependent on antibody tests for identifying whether people have been infected with the SARS-CoV-2 virus in the past. However, a new study in Italy has shown that these tests are not fully consistent. Experts have found that a new test, which detects T cells in the immune system, might be more reliable than traditional antibody tests. Scientists from the US, UK, and Italy have said that it is a well-known fact that antibodies reduce over time, whereas T cells carry an immunological memory. They have observed many people in Italy for validating the efficiency of this new testing method.
Experts have extracted blood samples of 70 people who have been diagnosed with COVID19 two months earlier. As expected, most of them have been tested positive during the antibody tests. However, antibody tests have shown negative results for 16 of the COVID19 cases, which means 23 percent of the cases, have not been identified by the antibody test. At the same time, T cell tests have missed only two cases, it shows that T cell tests have only a 3 percent possibility of error. Scientists have screened 2200 people who have not been diagnosed with COVID19 earlier. T cell test has been able to detect 45 of them with positive results. The co-author of the study, Dr. Lanco Baldo has said these 45 people have been infected with COVID19 in the past but have not realized until now. He has said that 25 out of 45 positive patients have been dealing with the symptoms of the disease at some point. He has noted that they might be living with a COVID19 positive person as well.
The company, which has developed this T cell test, is planning to launch this new testing method commercially in late November. The company is expected to file for approval of Emergency Use Authorization at the US Food and Drug Administration (FDA) soon. Past studies as well have shown that antibodies reduce over time. Unlike antibodies, T cells remain stable for a while. They persist for years in the case of other viruses. Although experts have been unsure about the duration of T cells’ stability in the case of the SARS-CoV-2 virus, however, they hope it will stay in the body for a couple of years at least. As per the latest report, T cells not just remain stable but they also remember how to ward off the same invader.