Design and implementation of a national program to monitor the prevalence of SARS-CoV-2 IgG antibodies in England using self-testing: the REACT-2 study - Ward, H; Atchison, C; Whitaker, M; Davies, B; Ashby, D; Darzi, A; Chadeau-Hyam, M; Riley, S; Donnelly, CA; Barclay, W; Cooke, GS; Elliott, P (American Journal of Public Health, 2023)