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As of 9 March 2020, 49,965 cases of novel coronavirus infection had been confirmed in Wuhan, of which 2,404 cases resulted in deaths – the fatality rate of COVID-19 in Wuhan is 4.8%. In other regions of Hubei province except Wuhan, there had been 17,795 confirmed cases, and 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, 12,994 confirmed cases were found, 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. Consequently, with different data used, the discussion about the risk of the novel coronavirus would lead to drastically different conclusions.
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 the Chinese Center for Disease Control and Prevention (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. Preventing novel coronavirus infection among high-risk groups, therefore, would significantly reduce the fatality rate of COVID-19. Important preventative measures include protection of elderly people from infection in hospitals and assisted living facilities, where susceptible groups are highly concentrated, as well as at home settings in the community.
Because of widespread community transmission in Wuhan, the elderly makes up 5% of the cases of infection, while in all of China including Wuhan, the number is only 3.2%. The timely detection and isolation of new cases outside Wuhan effectively prevented the epidemic from spreading from the more socially active young and middle-aged groups to the elderly and contributed to the lower fatality rate in general.
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 reduce interpersonal contact, mitigate the increase of new cases, and avoid the overloading of local healthcare systems. With early detection and early treatment of infected patients, the fatality rate of COVID-19 outside Wuhan is evidently lower. In the early stage of the outbreak in Wuhan, however, the overload of medical facilities and limited knowledge about this new virus led to unsatisfactory treatment results in many cases and thus the higher fatality rate. As a coordinated public health campaign against the epidemic, over 40,000 healthcare professionals arrived in Wuhan to provide support and two infectious disease hospitals (Huoshenshan Hospital and Leishenshan Hospital) and numerous makeshift hospitals started operating, which allowed all need for hospitalized care being met.
These measures significantly improved the capacity of the local healthcare system, lowered the risks of community transmission, and prevented the deterioration of patient health. The tension between the outbreak and the limited medical resources was thus considerably resolved. Additionally, the national treatment standard for COVID-19 has been updated to its seventh edition and post-hospitalization recovery plans were made, which indicated enhanced understanding of COVID-19. The treatment capacity in Wuhan has greatly improved in the later stage of the epidemic.
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. On 9 March, 19 new cases of COVID-19 were confirmed in Chinese mainland, a number that has remained low for some time, but there remain 4794 critical cases. The fatality rate of COVID-19 may still increase as time goes by.
Therefore, the different fatality rates in Wuhan and nationwide indicated the different fatality risk of COVID-19 in varying conditions. Other countries and regions should take the whole set of factors into consideration in data usage. The fatality rate in Wuhan, especially that when hospitalization needs were not fully met, is probably higher than the current figure of 4.8%, though no accurate data based on panel study are yet available. This represents the fatality rate when serious community transmission happens in a modern city of 10 million population with an extremely overloaded healthcare system. The fatality rate outside Wuhan, in comparison, represents the fatality level when good community prevention is in place and medical resources remain sufficient.
To reduce the risk of death caused by COVID-19, the essence is to prevent or delay widespread community transmission, thus avoiding the overload of public health systems and the infection of high-risk groups. It would also 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.
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