It is unsurprising that recovered COVID-19 patients have T cells that target the virus, with multiple studies highlighting this. What is surprising, however, is that there are people who do not possess COVID-19 antibodies but do possess T cells that target COVID-19.
Even more surprising is the fact that this was also seen in blood samples taken years before the coronavirus pandemic even began, meaning some people have pre-existing resistance against the virus. In fact, according to one study published in the academic journal Cell in May, these T cell responses were found in 40%-60% of unexposed individuals.
Indeed, the vaccine candidate being developed by AstraZeneca and Oxford University works by specifically encouraging the production of both antibodies and T cells.