Phase 1 COVID-19 Immunity - National Core Study

A person's immune response—how strong and well-targeted it is—determines whether a SARS-CoV-2 infection leads to mild illness or severe disease, and vaccines work by shaping that response. This programme, the National Core Study on COVID-19 Immunity (NCSi), coordinates and builds on existing UK investments in understanding immunity to the virus. It addresses a critical gap: while we know immunity matters, we lack a unified, large-scale picture of how immune responses vary across different people, how long protection lasts after infection or vaccination, and how to predict individual outcomes. Without this coordinated effort, data remains fragmented and harder to translate into practical guidance. If successful, the research will produce tools to predict who is most at risk from severe COVID-19, inform vaccine scheduling and booster strategies, and help design interventions that protect against both acute infection and longer-term complications such as long COVID. It also aims to prepare the UK for future pandemic threats by building a national infrastructure for immune surveillance. This is applied, policy-relevant science—its direct impact will be on clinical decision-making, public health guidance, and pandemic preparedness planning, not on everyday consumer technology.