Science and the Coronavirus: A model-based analysis that estimates the severity of COVID-19
A paper in the well-regarded medical journal “Lancet” retroactively recalculated the actual death rate in China from COVID-19. If one takes into account all the cases who were positive but never tested, the death rate comes to 0.66% rather than the 2-3% range originally considered.
As this pandemic progresses, the data surrounding it is also rapidly changing. Therefore, a range of case fatality ratio estimates for COVID-19 have been produced that differ substantially in magnitude. In this study, the authors aimed to provide robust estimates, accounting for censoring and ascertainment biases.
The authors did this by collecting individual-case data for patients who died from COVID-19 in Hubei, mainland China, and for cases outside of mainland China. These individual-case data were used to estimate the time between the onset of symptoms and outcome (death or discharge from hospital). They 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, age, and location.
They also estimated the case fatality ratio from individual line-list data on 1334 cases identified outside of mainland China.