New Rapid Blood Test Can Measure Immunity to COVID-19 and Vaccine Efficacy

Researchers from Mount Sinai and Duke-NUS Medical School have developed a rapid blood test that checks for T-cell response to SARS-CoV-2, the virus that causes COVID-19. The immune system produces T-cells to fight off viruses and can stay in the body longer than antibodies, making them a better indicator of long-term immunity

According to the news release, the blood test will allow large-scale monitoring of the population's immunity and vaccine efficacy that can help experts design revaccination strategies for vulnerable immunosuppressed individuals. Also, it could help researchers better understand who is likely to get a breakthrough COVID-19 case.

How T-Cells Work

T-cells are part of the immune system that targets specific foreign bodies. They circulate until they encounter their specific antigen instead of generically attacking antigens.

The Hill explains that the first thing the immune system does when a virus enters the body is either through infection or vaccination to create antibodies, which is part of humoral immunity. Then the immune system will activate T-cells that stop the virus from getting too serious when it starts to enter the cells.

Study co-lead author, oncological sciences, and pharmacological sciences Professor Ernesto Guccione from the Tisch Cancer Institute at Mount Sinai said that as long as there is a secondary immunity people will clear the virus out of their body within a few days or a week after getting infected and get on to live their lives.

The role of T cells could change throughout the lifetime. From being a critical part of building an infant's immunity to becoming long-term reserves of memory T-cells that are maintained through adulthood.

T-cells remain in the body for many years, unlike antibodies that leaves the body after the infection. That is why T-cells are a better long-term indication of immunity and something that the new blood test checks to measure a person's COVID-19 immunity.

Novel Blood Test Pinpoints Who Will Get Breakthrough COVID-19 Case

The new test is called dqTACTand can help predict the likelihood of breakthrough COVID-19 infections in fully-vaccinated individuals and help determine how frequently immunocompromised people need to be re-vaccinated. WebMD reported.

The new test takes less than 24 hours to perform and can be used on a large scale to measure the activation of T-cells. Also, the test adds synthetic viral peptides from the SARS-CoV-2 virus to a blood sample. The authors wrote that the test is deemed negative if there is no T-cell reaction within 24 hours.

It is positive if the peptides trigger T-cells. That is when the test could measure the strength of the body's immune response against COVID-19.

The test has already been validated against traditional laboratory testing in 91 people, wherein it is comprised of 50% who never had COVID-19 and another 50% who were infected and recovered from the infection. The feedback went well and the team found that it predicted the immune strength of up to 8 months after the second dose of the COVID-19 vaccine.

They noted that T-cell response was also greater among people with two doses of vaccine than those who only received one immunization. Further studies are still ongoing to meet the FDA requirements.

Check out more news and information on COVID-19 in Science Times.