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Sojin Choi 2 Articles
Viral shedding patterns of the symptomatic SARS-CoV-2 infection according to virus-type dominant periods and vaccination status in Gyeonggi Province, Korea
Gawon Choi, Ah-Young Lim, Sojin Choi, Kunhee Park, Soon Young Lee, Jong-Hun Kim
Epidemiol Health. 2022;e2023008.   Published online December 21, 2022
DOI:    [Accepted]
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AbstractAbstract PDF
We compared the viral cycle threshold (Ct) value of infected patients to better understand the viral kinetics during the dominant period in which a specific virus type according to the vaccination status in Gyeonggi Province, Republic of Korea.
We obtained case-specific data from the COVID-19 surveillance system, Gyeonggi in-depth epidemiologic report system, and Health Insurance Review & Assessment (HIRA) Service from January 2020 to January 2022. We defined the dominant periods according to the viral sequencing test result and explored Ct values. Using a generalized additive model, we performed a nonlinear regression analysis to determine viral kinetics over time.
Cases in the delta variant dominant period had higher viral shedding patterns than cases in other periods. The temporal change of virus shedding did not differ according to the vaccination status in the omicron variant dominant period but decreased in patients who completed the third vaccination in the delta variant dominant period. The time from symptom onset to peak viral shedding based on the E gene in the case of the omicron and delta variant dominant periods was approximately 2.4 days (95% CI: 2.2-2.5) and 2.1 days (95% CI: 95% CI: 2.0-2.1), respectively.
In the one-time tests conducted to diagnose SARS-CoV-2 infection in a large population, although individual characteristics were not adjusted, it was confirmed that the viral shedding differed according to the dominant strain and vaccination history. These analysis results give utilization value for hundreds of thousands of test data produced at SARS-CoV-2 screening test centers.
Korean summary
Key Message
COVID-19 outbreak in a military unit in Korea
Chanhee Kim, Young-Man Kim, Namwoo Heo, Eunjung Park, Sojin Choi, Sehyuk Jang, Nayoung Kim, Donghyok Kwon, Young-Joon Park, Byeongseop Choi, Beomman Ha, Kyounghwa Jung, Changbo Park, Sejin Park, Heeyoung Lee
Epidemiol Health. 2021;43:e2021065.   Published online September 8, 2021
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  • 2 Citations
AbstractAbstract AbstractSummary PDF
This study presents the response of a military unit to an outbreak of coronavirus disease 2019 (COVID-19) in Gyeonggi Province. As soon as 2 soldiers were identified as index cases, the infectious disease investigators of the Gyeonggi Provincial Government, Korea Disease Control and Prevention Agency, and the Armed Forces Epidemiologic Investigation Center discussed the investigation and response plan for an imminent massive outbreak.
The joint immediate response team (IRT) conducted interviews with confirmed COVID-19 patients, reviewed their medical records, performed contact tracing using global positioning system data, and undertook a field investigation. For risk assessment, the joint IRT visited all 8 sites of the military units and the army chaplain’s church to evaluate the transmission risk at each site. The evaluation items included the size of the site, the use of air conditioning, whether windows were opened, and whether masks were worn. Pooled testing was used for the low-risk population to quickly detect the spread of COVID-19 in the military base.
One day before the symptom onset of the index case, the lecturer and >50% of the attendees were infected with COVID-19 while attending a lecture that lasted 2 hours and 30 minutes. Attendees were not wearing masks and were in a poorly ventilated room.
Since COVID-19 can be spread before symptom onset, contact tracing must be performed to investigate potential exposures prior to symptom onset and to manage any exposed persons.
Korean summary
본 연구는 경기도 군부대에서 발생한 코로나19 대응 경험을 공유하는 국내 최초의 연구 결과이다. 본 연구를 통해 정리된 역학조사 과정은 군부대, 기숙사, 교정시설 등 집단 시설의 방역 대책 수립에 도움이 될 것으로 기대한다. 또한, 이번 사례는 집단 감염 발생 시 여러 유관 기관의 협조 체계가 신속한 대응과 추가 전파 예방에 중요하다는 점을 시사한다.
Key Message
This study is the first research in South Korea to share the experience of responding to COVID-19 at the military unit in Gyeonggi-do. The epidemiological investigation process organized through this study is expected to help establish response measures for group facilities such as military units, dormitories, and correctional facilities. In addition, this case suggests that the cooperative system of various related organizations in the event of a mass infection is important for rapid response and prevention of further transmission.


Citations to this article as recorded by  
  • Trends in Confirmed COVID-19 Cases in the Korean Military Before and After the Emergence of the Omicron Variant
    Dong Hoon Shin, Haebong Jang, Sangho Lee, Byung Seop Choi, Donghoon Kim, Hong Sang Oh
    Journal of Korean Medical Science.2022;[Epub]     CrossRef
  • Characteristics of COVID-19 outbreaks and risk factors for transmission at an army training center in South Korea from June to August 2021
    U Jin Cho, Seongjin Wang, Seonju Yi, Yeon Hwa Choi, Eun-Young Kim, Jin A Kim, Sanghwan Bae, Jungyeon Yu, Jangkyu Choi, Young-Joon Park
    Osong Public Health and Research Perspectives.2022; 13(4): 263.     CrossRef

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