PITCH: Covid-19 immunity studies in a UK Health Care Worker Cohort

Both infection and vaccination, alone or in combination, induce effective immune responses against SARS-CoV-2. The maintenance of such responses – and hence protection – however may differ. In a large prospective study of UK Healthcare Workers (PITCH, within the larger SIREN study) we previously observed that prior infection impacted strongly on subsequent cellular and humoral immunity induced after long and short dosing intervals of Pfizer-mRNA vaccination. We are now undertaking a longer term study of this cohort over 6-9 months following vaccination and also following a subsequent booster vaccination. We have observed a waning of protection over time post second dose seen most markedly in those without prior infection. The underlying immunologic features of this will be discussed.
Prof. Paul Klenerman is trained in medicine at Cambridge and Oxford and specialised in infectious diseases. After a PhD on HIV with Andrew McMichael and Rodney Philips in Oxford, he worked on LCMV in Zurich with Rolf Zinkernagel and Hans Hengartner. He had Wellcome funding to work on T cells and virus infection since then and have looked at T cell responses to CMV and to HCV, including development of vaccines. This includes studies of intrahepatic T cells, which led on to analysing the abundant unconventional T cell populations. In the Covid-19 response he helped integrate immunology studies from across Oxford, and established PITCH, a large collaboration focusing on T cell responses in UK Health Care Worker. He holds a chair at Oxford, working at the Translational Gastroenterology Unit and at the Medawar Building (Pathogen Research).