Changes in in-hospital mortality in the first wave of COVID-19: a multicentre prospective observational cohort study using the WHO Clinical Characterisation Protocol UK by Docherty, AB, Mulholland, RH, Lone, NI, Cheyne, CP, De Angelis, D, Diaz-Ordaz, K, Donegan, C, Drake, TM, Dunning, J, Funk, S, García-Fiñana, M, Girvan, M, Hardwick, HE, Harrison, J, Ho, A, Hughes, DM, Keogh, RH, Kirwan, PD, Leeming, G, Nguyen Van-Tam, JS, Pius, R, Russell, CD, Spencer, RG, Tom, BDM, Turtle, L, Openshaw, PJM, Baillie, JK, Harrison, EM, Semple, MG, Baillie, JK, Semple, MG, Openshaw, PJM, Carson, G, Alex, B, Bach, B, Barclay, WS, Bogaert, D, Chand, M, Cooke, GS, Docherty, AB, da Silva Filipe, A, Fletcher, T, Green, CA, Harrison, EM, Hiscox, JA, Ho, AYW, Horby, PW, Ijaz, S, Khoo, S