Imperial College London

Steven Riley

Faculty of MedicineSchool of Public Health

Professor of Infectious Disease Dynamics



+44 (0)20 7594 2452s.riley




UG8Medical SchoolSt Mary's Campus






BibTex format

author = {Verity, R and Okell, LC and Dorigatti, I and Winskill, P and Whittaker, C and Imai, N and Cuomo-Dannenburg, G and Thompson, H and Walker, PGT and Fu, H and Dighe, A and Griffin, JT and Baguelin, M and Bhatia, S and Boonyasiri, A and Cori, A and Cucunub√°, Z and FitzJohn, R and Gaythorpe, K and Green, W and Hamlet, A and Hinsley, W and Laydon, D and Nedjati-Gilani, G and Riley, S and van, Elsland S and Volz, E and Wang, H and Wang, Y and Xi, X and Donnelly, CA and Ghani, AC and Ferguson, NM},
doi = {10.1016/S1473-3099(20)30243-7},
journal = {Lancet Infectious Diseases},
pages = {669--677},
title = {Estimates of the severity of coronavirus disease 2019: a model-based analysis.},
url = {},
volume = {20},
year = {2020}

RIS format (EndNote, RefMan)

AB - BACKGROUND: In the face of rapidly changing data, a range of case fatality ratio estimates for coronavirus disease 2019 (COVID-19) have been produced that differ substantially in magnitude. We aimed to provide robust estimates, accounting for censoring and ascertainment biases. METHODS: We collected individual-case data for patients who died from COVID-19 in Hubei, mainland China (reported by national and provincial health commissions to Feb 8, 2020), and for cases outside of mainland China (from government or ministry of health websites and media reports for 37 countries, as well as Hong Kong and Macau, until Feb 25, 2020). These individual-case data were used to estimate the time between onset of symptoms and outcome (death or discharge from hospital). We next obtained age-stratified estimates of the case fatality ratio by relating the aggregate distribution of cases to the observed cumulative deaths in China, assuming a constant attack rate by age and adjusting for demography and age-based and location-based under-ascertainment. We also estimated the case fatality ratio from individual line-list data on 1334 cases identified outside of mainland China. Using data on the prevalence of PCR-confirmed cases in international residents repatriated from China, we obtained age-stratified estimates of the infection fatality ratio. Furthermore, data on age-stratified severity in a subset of 3665 cases from China were used to estimate the proportion of infected individuals who are likely to require hospitalisation. FINDINGS: Using data on 24 deaths that occurred in mainland China and 165 recoveries outside of China, we estimated the mean duration from onset of symptoms to death to be 17·8 days (95% credible interval [CrI] 16·9-19·2) and to hospital discharge to be 24·7 days (22·9-28·1). In all laboratory confirmed and clinically diagnosed cases from mainland China (n=70117), we estimated a crude case fatality ratio (adjusted for cen
AU - Verity,R
AU - Okell,LC
AU - Dorigatti,I
AU - Winskill,P
AU - Whittaker,C
AU - Imai,N
AU - Cuomo-Dannenburg,G
AU - Thompson,H
AU - Walker,PGT
AU - Fu,H
AU - Dighe,A
AU - Griffin,JT
AU - Baguelin,M
AU - Bhatia,S
AU - Boonyasiri,A
AU - Cori,A
AU - Cucunub√°,Z
AU - FitzJohn,R
AU - Gaythorpe,K
AU - Green,W
AU - Hamlet,A
AU - Hinsley,W
AU - Laydon,D
AU - Nedjati-Gilani,G
AU - Riley,S
AU - van,Elsland S
AU - Volz,E
AU - Wang,H
AU - Wang,Y
AU - Xi,X
AU - Donnelly,CA
AU - Ghani,AC
AU - Ferguson,NM
DO - 10.1016/S1473-3099(20)30243-7
EP - 677
PY - 2020///
SN - 1473-3099
SP - 669
TI - Estimates of the severity of coronavirus disease 2019: a model-based analysis.
T2 - Lancet Infectious Diseases
UR -
UR -
UR -
UR -
VL - 20
ER -