Clinical use of convalescent plasma in the COVID-19 pandemic: a transfusion-focussed gap analysis with recommendations for future research priorities by Al-Riyami, AZ, Schäfer, R, van den Berg, K, Bloch, EM, Estcourt, LJ, Goel, R, Hindawi, S, Josephson, CD, Land, K, McQuilten, ZK, Spitalnik, SL, Wood, EM, Devine, DV, So-Osman, C