A Korean research team has suggested that the interpretation of the lethality of the new coronavirus, one of the indicators showing the severity of COVID-19, should be made more prudently.
Hallym University Department of Social and Preventive Medicine Professors Kim Dong-hyun and Choe Young-june and Research Institute of Clinical Epidemiology Professor Jeong Jin-young have recently released a research paper by assessing CFR and their interpretations.
The CFR comes by dividing the number of total confirmed cases by that of deaths. Countries have used CFR to assess and compare the disease’s degree of risks as well as their ability to cope with infectious diseases.
However, the crude death rate from the aggregated data does not give a precise and timely estimate, as the disease continues to spread and kill people. The final CFR will also differ from that of the early period of the outbreak.
|A graph of the case fatality rates in selected countries with confirmed cases and death from the new coronavirus as of March 25 (Credit: World Health Organization).|
According to the research team, Korea’s cumulative CFR was about 1.3 percent as of March 25, compared with those of Italy, Iran, Spain, and China, which stood at 9.5, 7.9, 6.6, and 4.0 percent, respectively.
Korea’s CFR could have been affected by the larger share of the younger people becoming infected, it said. The fatality rate of age-adjusted data shows differently. The adjusted data showed Italy’s fatality rate was 4.2 percent as of March 17 compared to Korea’s 2.4 percent by March 24.
|A table of an age-specific and adjusted case fatality rate in Korea, Italy, and China at different times for each nation (Credit: Ministry of Health and Welfare).|
The research team stressed that the patients’ age has to be considered in interpretation based on the CFR. It also added that an age-specific CFR would show a more valid comparison between countries.
The rate may not reflect the correct number of deaths and confirmed cases occurred due to different testing capabilities and health response policy among the nations. Countries with low medical capacity are less likely to test and provide service to patients, which will result in higher CFR.
“The exact CFR that reflects the true lethality is likely to be aggregated when the pandemic begins to settle down after months,” the research team said.
Besides, the research team said that the fatality rate should be interpreted cautiously by taking into account the time difference between COVID-19 confirmation and death.
“Estimating the CFR is a high priority in response to COVID-19, and interpretation must be made cautiously in the middle of the pandemic to draw causal inferences from visible data,” the researchers said.
The article was published in the Journal of Korean Medical Science under the title of “Understanding and Interpretation of Case Fatality Rate of Coronavirus Disease 2019” on Monday.
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