Development and validation of a simple cellular immunity test (SCIT) for SARS-CoV-2 (Covid-19)

As the current Covid-19 coronavirus pandemic unfolds, we urgently require screening tools that determine who has been infected with the SARS-CoV-2 virus which causes the disease. To enable the population and the economy to return to normal it is important to know who has become immune to the virus. This includes individuals who have already been infected, in some cases without realising it.
In order to gain immunity to SARS-CoV-2, an individual must generate an adequate immune response that protects from future infection. This can be measured by looking for antibodies found in blood samples that bind specifically to the virus. A number of companies have attempted to manufacture a test that determines whether an individual has these antibodies present in their blood. However, as widely reported, all these tests have failed to meet reliability criteria and thus have not been approved for widespread use. Technical hurdles with this type of test may continue to hold up their use. We propose a different type of immunity test, utilising existing laboratory tests.

Long-term protection against viruses not only comes from antibodies, but from cells of the immune system called 'T cells', which play a critical role in controlling and eradicating viral infections. From a single tube of blood, we can identify the presence of T cells that respond to the SARS-CoV-2 virus. This approach is potentially more sensitive at determining immunity than antibody testing, but this needs verifying on patients that have recovered from Covid-19. Patients will be recruited by our long-standing clinical colleagues at the University Hospital of Wales, Cardiff, (Prof Andrew Godkin and Prof Paul Morgan) to determine whether a laboratory test for the presence of these T cells is a feasible alternative to the antibody test. This alternative approach would provide the same information about whether an individual has been infected with the virus and generated immunity to it. In addition, when a vaccine does become available, results from the test developed here will yield critical additional information as to whether an adequate immune response that protects individuals from SARS-CoV-2 infection has been generated.

Following on from the success of the grant so far in determining if a person has T cells that respond to the SARS-CoV-2 virus from just tube of blood, the “Extension for Impact” funding will provide the necessary support to recruit more individuals into the study. This will provide a larger data set and provide the necessary information required to gain MHRA approval, CE markings and further validations of the test, thus allowing the test to be commercialised. Knowing their immune status will have a huge impact on those people in the ‘vulnerable’ category currently living with the anxiety of whether they have had the virus. Making the test available to vaccine manufacturers will also enable them to assess the long-term success of the vaccines currently in development.