Protocol for an OpenSAFELY cohort study collecting patient-reported outcome measures using the TPP Airmid smartphone application and linked big data to quantify the health and economic costs of long COVID (OpenPROMPT). - Herrett E; Tomlin K; Lin LY; Tomlinson LA; Jit M; Briggs A; Marks M; Sandmann F; Parry J; Bates C; Morley J; Bacon S; et al. (BMJ open, 2023)