• Written By:
    Comprehensive Ophthalmology

    Review of: Estimates of the severity of coronavirus diseases 2019: a model-based analysis

    Verity R, Okell L, Dorigatti I, et al. The Lancet, in press

    This study provides robust case fatality ratio estimates for COVID-19, taking into account censoring and ascertainment bias.

    Study design

    Researchers used data on 24 patients who died from the disease in Hubei, China, to estimate the onset-to-death distribution. The data were originally reported by the National Health Commission and the Hubei Province Health Commission website up to February 8, 2020. The study also included data on 2,010 cases from 37 countries and 2 special administrative regions of China (Hong Kong and Macau). This information was collected from government or ministry of health websites and media reports until February 25, 2020.


    Based on the 24 deaths in mainland China and 165 recoveries internationally, the mean duration from symptom onset to death was 17.8 days and the average time to hospital discharge was 24.7 days. The best estimate of the case fatality ratio in China was 1.38%. However, this ratio was significantly higher among individuals aged 60 years or older (6.4% vs. 0.32%) and was up to 13.4% among those aged 80 years or older. Estimates of case fatality ratio in international cases stratified by age were consistent with data from China.


    Most of the data for fatality rates are based on data from Wuhan, China. As other communities around the world experience outbreaks of this pandemic, these new datasets may differ from what was observed in China.

    Clinical significance

    It is important to understand which patients and age groups have the highest risk of mortality from COVID-19. This can help physicians determine which patients need to leave their homes and come to the office to be examined and treated.