As well as death, severe COVID-19 disease has effects on many different organ systems. In this study, published in The Lancet, we characterised the burden of complications and organ injury in 73,197 patients admitted to hospital between January and August 2020. We found that nearly 1 in 2 people had at least one complication. Having a complication was associated with higher rates of critical care admission and mortality. When we studied predictors of complications, we identified that unlike in the case of mortality, where older, more frail people had a higher chance of death, younger people were also at risk of developing complications. This study received international media attention and coverage from the BBC, ABC, Sky news, ITV, STV and most major UK newspapers. This work was also the subject of a system-wide NIHR update.