New Numbers From China Suggests Far Lower Incidence Of Death Than Early Estimates

The probability of dying after developing coronavirus symptoms is 1.4% in Wuhan, China, new research suggests — far lower than initial estimates

Aylin Woodward

• More than 227,000 people have been infected with the new coronavirus worldwide, and 9,300 have died. The city of Wuhan, China, where the outbreak started, was hardest hit.
• According to a new study about the Wuhan cases, the chance a patient who shows coronavirus symptoms dies is 1.4%.
• That figure is much lower than previous estimates for Wuhan.
• The researchers found that symptomatic patients older than 59 were five times more likely to die from the coronavirus than people between the ages of 30 and 59.

A study published today in the journal Nature Medicine suggests that the chances a patient in Wuhan, China, would die after developing symptoms was 1.4% as of February 29.

This figure — what the authors call symptomatic case-fatality risk — is far lower than previous death-rate estimates for Wuhan, which ranged from 2% to 4.5%. That's because the researchers' case-fatality risk wasn't based solely on the proportion of deaths out of the total number of reported cases, which is how death rates are calculated. Instead, they attempted to incorporate estimations of unreported cases into their figures. 

The authors also found that symptomatic case-fatality risk increased with age: "There is a clear and considerable age dependency in symptomatic infection (susceptibility) and outcome (fatality) risks," they wrote.

In addition to calculating overall case-fatality risk, the researchers broke down that risk by age bracket.

They found that symptomatic patients older than 59 were 5.1 times more likely to die from the coronavirus than people between the ages of 30 and 59. Patients younger than 30 were about half as likely to die.

What's more, the risk of symptomatic infection increased by about 4% with each year of age among adults between the ages of 30 and 60. 

People between ages 60 and 79 were about twice as susceptible to symptomatic infection as people aged 40 to 49, and about three times more susceptible than people aged 30 to 39.

The researchers also said the 1.4% estimate of case-fatality risk may not apply to other places outside of Wuhan —  the rates outside of Wuhan could be even lower.

"The precise fatality-risk estimates may not generalize to those outside of that original epicenter, especially during subsequent phases of the epidemic," they wrote. "The increasing availability of newer, and potentially better, treatment modalities to more patients would presumably lead to fewer deaths."