Surveillance of COVID-19 is one aspect of the UK’s pandemic response which is widely recognised as world leading. This event will show how two of the main surveillance studies – the ONS Covid Infection Survey and the Imperial College London REACT surveys – were carried out. Ruth Studley of the Office for National Statistics will describe how the Covid Infection Survey was set out, the challenges involved, and what analysis the longitudinal survey enabled. Nicholas Gilby of Ipsos will explain how the REACT surveys were designed, how their designs were adapted over time to meet a variety of challenges, and how the surveys were implemented. Gerry Nicolaas of NatCen Social Research will discuss the strengths and weaknesses of the study approaches. There will be an opportunity to ask questions.