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Okyu Kwon 2 Articles
Evidence of the importance of contact tracing in fighting COVID-19
Okyu Kwon
Epidemiol Health. 2022;44:e2022006.   Published online January 3, 2022
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  • 483 Download
AbstractAbstract AbstractSummary PDF
We analyzed data to determine whether there are distinguishing characteristics depending on the success or failure of control for coronavirus disease 2019 (COVID-19) by country in the trend of the daily number of confirmed cases and the number of tests.
We obtained the number of confirmed cases and tests per day for almost every country in the world from Our World in Data. The Pearson correlation between the two time series was calculated according to the time delay to analyze the relationship between the number of tests and the number of cases with a lag.
For each country, we obtained the time lag that makes the maximum correlation between the number of confirmed cases and the number of tests for COVID-19. It can be seen that countries whose time lag making maximum correlation lies in a special section between about 15 days and 20 days are generally been successful in controlling COVID-19. That section looks like a trench on the battlefield.
We have seen the possibility that the success in mitigating COVID-19 can be expressed as a simple indicator of the time lag of the correlation between confirmed cases and tests. This time lag indicator is presumably reflected by efforts to actively trace the infected persons.
Korean summary
일일 신규 확진자 수와 검사자 수 시계열의 상관관계에서의 시간지연 값은 방역의 성공을 평가할 수 있는 지표가 될 수 있음을 여러 국가의 실제 데이터로부터 확인할 수 있었다. 이 시간 지연은 역학 조사에 따른 감염자 발굴의 노력의 결과로 이해할 수 있을 것이다.
Key Message
It was confirmed from actual data from several countries that the time delay value in the correlation between the number of daily new confirmed cases and the number of tests can be an indicator to evaluate the success of quarantine. This time delay can be understood as a result of efforts to discover infected persons according to epidemiological investigations.
Intervention effects in the transmission of COVID-19 depending on the detection rate and extent of isolation
Okyu Kwon, Woo-Sik Son, Jin Yong Kim, Jong-Hun Kim
Epidemiol Health. 2020;42:e2020045.   Published online June 23, 2020
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  • 269 Download
  • 3 Citations
AbstractAbstract AbstractSummary PDFSupplementary Material
In 2020, the coronavirus disease 2019 (COVID-19) respiratory infection is spreading in Korea. In order to prevent the spread of an infectious disease, infected people must be quickly identified and isolated, and contact with the infected must be blocked early. This study attempted to verify the intervention effects on the spread of an infectious disease by using these measures in a mathematical model.
We used the susceptible-infectious-recovery (SIR) model for a virtual population group connected by a special structured network. In the model, the infected state (I) was divided into I in which the infection is undetected and Ix in which the infection is detected. The probability of transitioning from an I state to Ix can be viewed as the rate at which an infected person is found. We assumed that only those connected to each other in the network can cause infection. In addition, this study attempted to evaluate the effects of isolation by temporarily removing the connection among these people.
In Scenario 1, only the infected are isolated; in Scenario 2, those who are connected to an infected person and are also found to be infected are isolated as well. In Scenario 3, everyone connected to an infected person are isolated. In Scenario 3, it was possible to effectively suppress the infectious disease even with a relatively slow rate of diagnosis and relatively high infection rate.
During the epidemic, quick identification of the infected is helpful. In addition, it was possible to quantitatively show through a simulation evaluation that the management of infected individuals as well as those who are connected greatly helped to suppress the spread of infectious diseases.
Korean summary
본 연구는 행위자 기반 모형의 시뮬레이션 평가를 통해 COVID-19 유행 상황에서 비약물적 중재 효과를 정량적으로 제시하였다. 비약물적 중재에 관한 세 가지 시나리오를 통해 제시한 결과에서, COVID-19 감염자를 신속하게 진단하고, 감염자 본인과 접촉자들을 가능한 한 빨리 모두 격리하여 관리하는 것이 감염병 확산을 억제하는데 있어서 보다 효과적이었다.
Key Message


Citations to this article as recorded by  
  • Mathematical Modeling of COVID-19 Transmission and Intervention in South Korea: A Review of Literature
    Hyojung Lee, Sol Kim, Minyoung Jeong, Eunseo Choi, Hyeonjeong Ahn, Jeehyun Lee
    Yonsei Medical Journal.2023; 64(1): 1.     CrossRef
  • Non-pharmaceutical interventions during the COVID-19 pandemic: A review
    Nicola Perra
    Physics Reports.2021; 913: 1.     CrossRef
  • Dissection of non-pharmaceutical interventions implemented by Iran, South Korea, and Turkey in the fight against COVID-19 pandemic
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    Journal of Diabetes & Metabolic Disorders.2021; 20(2): 1919.     CrossRef

Epidemiol Health : Epidemiology and Health