COVID-19 fatality rates may be lower than initially reported, higher than influenza

The data on COVID-19 changes from day-to-day, and researchers say that initial estimates of the number of novel coronavirus infections that led to death from COVID-19 may have been overestimated, because of the small sample size they obtained data for early in the outbreak.

Researchers Robert Verity, Lucy C Okell, Ilaria Dorigatti, Peter Winskill, Charles Whittaker, Natsuko Imai, Gina Cuomo-Dannenburg, Hayley Thompson, Patrick G T Walker, Han Fu, Amy Dighe, Jamie T Griffin, Marc Baguelin, Sangeeta Bhatia, Adhiratha Boonyasiri, Anne Cori, Zulma Cucunubá, Rich FitzJohn, Katy Gaythorpe, Will Green, Arran Hamlet, Wes Hinsley, Daniel Laydon, Gemma Nedjati-Gilani, Steven Riley, Sabine van Elsland, Erik Volz, Haowei Wang, Yuanrong Wang, Xiaoyue Xi, Christl A Donnelly, Azra C Ghani, and Neil M Ferguson examined a larger dataset for patients in Hubei Mainlaind China, the Diamond Princess Cruise Ship, and returning expats to Wuhan. 

They determined that the fatality rate of COVID-19 in China was 1.38 percent.

As they gathered the data, estimated the time between when patients showed symptoms and when they were released from the hospital or died. They categorized these patients by age to come up with case fatality ratios for different age ranges.

Using 24 deaths in mainland China and 165 recoveries outside of China, the research team, determined that the span of time from symptom onset to death was 17.8 days, and for those who were discharged, that timeframe was 24.7 days.

For individuals under 60, the fatality rate is estimated at .27-.38 percent; for those who are 60 or older, the fatality rate is estimated at 6.4, and for patients who were 80 or older, it’s up to 13.4 percent.

They state, “adjusting for differences in underlying demography and assuming no overall difference in the attack rate by age, we estimated high under-ascertainment of cases in younger age groups both inside and outside of Wuhan.”

This research was funded by the UK Medical Research Council.