Oxford Immunotec Global PLC announced the release of data from a prospective cohort study in keyworkers in the UK " a collaboration between the Company and Public Health England (PHE). The data demonstrates that SARS-CoV-2 reactive T cells may be sufficient to give protection from COVID-19 and that serology alone may underestimate those at lower risk of clinical SARS-CoV-2 infection. The paper published on MedRxiv ‘SARS-CoV-2 responsive T cell numbers are associated with protection from COVID-19: A prospective cohort study in keyworkers’, presents data generated as part of the EDSAB-HOME study which investigated both antibody (serology) and T cell responses in a cohort of police, fire and healthcare workers. In the study, T cell tests were conducted at enrolment in almost 3,000 participants using the Company’s standardised research use only T-SPOT®Discovery SARS-CoV-2 assay. These individuals were then followed up for subsequent development of symptomatic, PCR confirmed SARS-CoV-2 infection. None of the participants with a high T cell response developed symptomatic SARS-CoV-2 infection in the follow-up period, whereas amongst those with low T cell responses there were 20 confirmed infections. Further follow-up is planned allowing for updated analyses as case numbers rise which may help yield additional insights into disease risk. These, and additional results from the data, suggest that: Serology alone may underestimate the working age population at lower risk of clinical SARS-CoV-2 infection. Individual level risk stratification may be possible using T cell assays. Numbers of individuals with high levels of SARS-CoV-2 responsive T cells declines with increasing age, specifically in the absence of antibodies (serology), and this may explain higher illness incidence and severity in this group. The T-SPOT Discovery SARS-CoV-2 test detected PCR confirmed SARS-CoV-2 infections that were not positive in antibody (serology) testing.