Hewitt, J., Carter, B., Vilches-Moraga, A., Quinn, T., Braude, P., Verduri, A., Pearce, L., Stechman, M., Short , R., Price, A., Collins, J., Bruce, E., Einarsson, A., Rickard , F., Mitchell, E., Holloway, M., Hesford, J., Barlow-Pay, F., Clini, E., Myint, P., Moug, S. & McCarthy, K. 2020, 'The effect of frailty on survival in patients with COVID-19 (COPE): a multicentre, European, observational cohort study', Lancet Public Health, 5(8), pp. 444-451. https://doi.org/10.1016/S2468-2667(20)30146-8