CD4+ and CD8+ T cells and antibodies are associated with protection against Delta vaccine breakthrough infection: a nested case-control study within the PITCH study.
Neale I., Ali M., Kronsteiner B., Longet S., Abraham P., Deeks AS., Brown A., Moore SC., Stafford L., Dobson SL., Plowright M., Newman TAH., Wu MY., Crick COVID Immunity Pipeline None., Carr EJ., Beale R., Otter AD., Hopkins S., Hall V., Tomic A., Payne RP., Barnes E., Richter A., Duncan CJA., Turtle L., de Silva TI., Carroll M., Lambe T., Klenerman P., Dunachie S., PITCH Consortium None.
Defining correlates of protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine breakthrough infection informs vaccine policy for booster doses and future vaccine designs. Existing studies demonstrate humoral correlates of protection, but the role of T cells in protection is still unclear. In this study, we explore antibody and T cell immune responses associated with protection against Delta variant vaccine breakthrough infection in a well-characterized cohort of UK Healthcare Workers (HCWs). We demonstrate evidence to support a role for CD4+ and CD8+ T cells as well as antibodies against Delta vaccine breakthrough infection. In addition, our results suggest a potential role for cross-reactive T cells in vaccine breakthrough.