@Article{info:doi/10.2196/20992,
author="Lee, Seung Won
and Yuh, Woon Tak
and Yang, Jee Myung
and Cho, Yoon-Sik
and Yoo, In Kyung
and Koh, Hyun Yong
and Marshall, Dominic
and Oh, Donghwan
and Ha, Eun Kyo
and Han, Man Yong
and Yon, Dong Keon",
title="Nationwide Results of COVID-19 Contact Tracing in South Korea: Individual Participant Data From an Epidemiological Survey",
journal="JMIR Med Inform",
year="2020",
month="Aug",
day="25",
volume="8",
number="8",
pages="e20992",
keywords="COVID-19; contact tracing; coronavirus; South Korea; survey; health data; epidemiology; transmission",
abstract="Background: Evidence regarding the effectiveness of contact tracing of COVID-19 and the related social distancing is limited and inconclusive. Objective: This study aims to investigate the epidemiological characteristics of SARS-CoV-2 transmission in South Korea and evaluate whether a social distancing campaign is effective in mitigating the spread of COVID-19. Methods: We used contract tracing data to investigate the epidemic characteristics of SARS-CoV-2 transmission in South Korea and evaluate whether a social distancing campaign was effective in mitigating the spread of COVID-19. We calculated the mortality rate for COVID-19 by infection type (cluster vs noncluster) and tested whether new confirmed COVID-19 trends changed after a social distancing campaign. Results: There were 2537 patients with confirmed COVID-19 who completed the epidemiologic survey: 1305 (51.4{\%}) cluster cases and 1232 (48.6{\%}) noncluster cases. The mortality rate was significantly higher in cluster cases linked to medical facilities (11/143, 7.70{\%} vs 5/1232, 0.41{\%}; adjusted percentage difference 7.99{\%}; 95{\%} CI 5.83 to 10.14) and long-term care facilities (19/221, 8.60{\%} vs 5/1232, 0.41{\%}; adjusted percentage difference 7.56{\%}; 95{\%} CI 5.66 to 9.47) than in noncluster cases. The change in trends of newly confirmed COVID-19 cases before and after the social distancing campaign was significantly negative in the entire cohort (adjusted trend difference --2.28; 95{\%} CI --3.88 to --0.68) and the cluster infection group (adjusted trend difference --0.96; 95{\%} CI --1.83 to --0.09). Conclusions: In a nationwide contact tracing study in South Korea, COVID-19 linked to medical and long-term care facilities significantly increased the risk of mortality compared to noncluster COVID-19. A social distancing campaign decreased the spread of COVID-19 in South Korea and differentially affected cluster infections of SARS-CoV-2. ",
issn="2291-9694",
doi="10.2196/20992",
url="http://medinform.jmir.org/2020/8/e20992/",
url="https://doi.org/10.2196/20992",
url="http://www.ncbi.nlm.nih.gov/pubmed/32784189"
}