As of 9 March 2020, the fatality rate of COVID-19 in Wuhan is 4.8%. In other regions of Hubei province except Wuhan, there had been 620 patient deaths, with a fatality rate of 3.5%. While in all of Chinese mainland (i.e. data of Hong Kong, Macao, and Taiwan excluded) aside from Hubei, causing 112 deaths and a fatality rate of 0.86%.
Apparently, there is a considerable gap in fatality rates of COVID-19 in different parts of China.
The fatality rate, and the variance thereof, however, is not only an indicator of the pathogenicity of the virus, but also depends on the age structure and preexisting health conditions of those infected, the operation of the healthcare system in different times and locations, and the accessibility of testing as well as the time when fatality rate is calculated.
Firstly, the age structure and the underlying health conditions of the patients are important factors behind the fatality rate.
A research by CCDC on more than 70,000 confirmed and suspected cases of COVID-19 as of 11 February found a general fatality rate of 2.3%, while the fatality rate for patients over 80 years old being 14.8%, 10.5% for patients with cardiovascular diseases, 0.2% for patients between 20-30 years old, and 0.9% for patients without underlying disease.
Secondly, the accessibility of timely medical care and the operation of local healthcare systems also have great impact on the fatality rate.
The lockdown measures in Wuhan gave other regions a valuable window of time for disease control and prevention, where necessary measures were taken to mitigate the increase of new cases and avoid the overloading of local healthcare systems.
Thirdly, although the range of testing and the time of fatality rate data collection do not change the risk of a disease, they can affect the judgment about the risk of the disease and the public health situation in general.
Since most cases of novel coronavirus infection present mild or no symptoms, it is extremely difficult to detect all cases of infection if no large-scale surveillance testing is implemented. Patients with more serious symptoms, on the other hand, are more likely to seek medical help, a tendency that would make the calculated fatality rate higher than it really is.
Ultimately, considering the progression of an outbreak, an accurate calculation of fatality rate is only possible after the epidemic.
A study published in The Lancet by Huazhong University of Science and Technology with other organizations shows that the average duration from the onset of COVID-19 to the start of ICU care is 16 days, and that patient death typically happens after 7 days in the ICU. The fatality rate could be relatively low in the early outbreak and increase as the epidemic progresses.
It would considerably reduce the fatality rate if anti-viral medication and vaccines are successfully developed and applied. The global research community is collaborating to make breakthrough in this field at the moment.