COVID-19: Original Article
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Direct indicators of social distancing effectiveness in COVID-19 outbreak stages: a correlational analysis of case contacts and population mobility in Korea
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Sojin Choi, Chanhee Kim, Kun-Hee Park, Jong-Hun Kim
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Epidemiol Health. 2023;45:e2023065. Published online July 10, 2023
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DOI: https://doi.org/10.4178/epih.e2023065
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Abstract
Summary
PDFSupplementary Material
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Abstract
OBJECTIVES
The effectiveness of social distancing during the coronavirus disease 2019 (COVID-19) pandemic has been evaluated using the magnitude of changes in population mobility. This study aimed to investigate a direct indicator—namely, the number of close contacts per patient with confirmed COVID-19.
METHODS
From week 7, 2020 to week 43, 2021, population movement changes were calculated from the data of two Korean telecommunication companies and Google in accordance with social distancing stringency levels. Data on confirmed cases and their close contacts among residents of Gyeonggi Province, Korea were combined at each stage. Pearson correlation analysis was conducted to compare the movement data with the change in the number of contacts for each confirmed case calculated by stratification according to age group. The reference value of the population movement data was set using the value before mid-February 2020, considering each data’s characteristics.
RESULTS
In the age group of 18 or younger, the number of close contacts per confirmed case decreased or increased when the stringency level was strengthened or relaxed, respectively. In adults, the correlation was relatively low, with no correlation between the change in the number of close contacts per confirmed case and the change in population movement after the commencement of vaccination for adults.
CONCLUSIONS
The effectiveness of governmental social distancing policies against COVID-19 can be evaluated using the number of close contacts per confirmed case as a direct indicator, especially for each age group. Such an analysis can facilitate policy changes for specific groups.
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Summary
Korean summary
1. 사회적 거리두기의 효과를 간접적인 자료인 이동통신사와 구글데이터를 이용하여 인구 이동성 변화의 크기를 평가하였고, 직접적인 자료인 역학조사서의 확진자 1인당 밀접 접촉자 수를 산출하여 비교 평가하였다.
2. 18세 이하 연령대는 사회적 거리두기의 강화 또는 완화 단계에 따라 확진자 1인당 밀접 접촉자 수가 민감하게 변동되었으나, 성인의 경우에는 덜 민감하게 변동되었다.
3. 역학조사서에 기반하여 시계열 자료로 재가공한 확진자 1인당 밀접 접촉자 수는 사회적 거리두기 정책의 효과를 평가하는 직접적인 평가 지표로 사용될 수 있기에 충분히 검토되어야 한다.
Key Message
1. The study assessed social distancing's effectiveness by analyzing population mobility changes through mobile operator and Google data. And it was also compared with the number of close contacts per confirmed COVID-19 case based on the epidemiological survey report.
2. Younger age groups were more influenced by the social distancing policy in close contacts per confirmed COVID-19 case than adults.
3. The study suggests using close contacts per confirmed COVID-19 case from the epidemiological survey report as a direct measure of social distancing policy effectiveness.