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expert reaction to a preprint on responsive T cell numbers and associated protection from COVID-19, as referred to in the PHE ‘Evaluating detection of SARS-CoV-2: AntiBodies at Home study’ report which was updated yesterday

A preprint, an unpublished non-peer reviewed study, posted on MedRxiv looks at responsive T cell numbers and associated protection from COVID-19, as referred to in yesterday’s updated version of the Evaluating Detection of SARS-CoV-2 AntiBodies at Home (EDSAB-HOME) study report.


*This is NOT a third-party comment* Dr David Wyllie, Consultant Microbiologist at Public Health England and the lead author of the study, said:

“We conducted a prospective cohort study in almost three thousand volunteers working in hospitals, and the fire and police services in England. Four months into the study, 20 participants with lower T cell responses had developed COVID-19, compared with none among individuals with higher T cell responses. This suggests individuals with higher numbers of T-cells recognising SARS-CoV-2 may have some level of protection from COVID-19, although more research is required to confirm this.”

Additional background

  • 2,847 participants joined a study and gave blood samples in June 2020.  PHE were able to follow up 2,826 of these for about 4 months to determine whether they developed COVID-19. 
  • On joining the study, T cells recognising SARS-CoV-2 and present in the blood were measured using a new ‘T-SPOT’ laboratory test developed by Oxford Immunotec Ltd. 
  • The authors identified a subgroup in the population with higher levels of T cells, meaning levels similar to those seen in people who had had confirmed COVID-19 infection.  A proportion of these individuals also had antibodies against SARS-CoV-2.
  • The authors are continuing to follow up this cohort and plan to publish further analyses soon.
  • If these results are confirmed in other, larger studies, measuring T-cell responses to SARS-CoV-2 may help identify individuals at risk of COVID-19.
  • This study did not assess whether T-cell responses were associated with participants being infectious or becoming infected without symptoms.


Dr Rupert Beale, Group Leader, Cell Biology of Infection Laboratory, Francis Crick Institute, said:

“About a quarter had highly reactive T cells, more than half of them had serological evidence of prior infection using tests that would be about 70% sensitive – so only a very small proportion of adults (less than 10%, maybe much less than 10%) would be protected by pre-existing T cell immunity.”



‘SARS-CoV-2 responsive T cell numbers are associated with protection from COVID-19: A prospective cohort study in keyworkers’ by David Wyllie et al was posted on MedRxiv on 4 November

The ‘What we have discovered so far section’ of ‘Evaluating detection of SARS-CoV-2: AntiBodies at Home study’ was updated on 18 November.



All our previous output on this subject can be seen at this weblink:



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