Early risk assessment for COVID-19 patients from emergency department data using machine learning by Heldt, FS, Vizcaychipi, MP, Peacock, S, Cinelli, M, McLachlan, L, Andreotti, F, Jovanović, S, Dürichen, R, Lipunova, N, Fletcher, RA, Hancock, A, McCarthy, A, Pointon, RA, Brown, A, Eaton, J, Liddi, R, Mackillop, L, Tarassenko, L, Khan, RT