Nationwide Results of COVID-19 Contact Tracing in South Korea: Individual Participant Data From an Epidemiological Survey

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.

Precision Mapping of COVID-19 Vulnerable Locales by Epidemiological and Socioeconomic Risk Factors, Developed Using South Korean Data

“…Contact tracing-based testing increases the likelihood of capturing asymptomatic cases. Korean tracing system has been reported as the global best practice lending to its advanced information technology system and data extensions through large consumer and healthcare databases (global positioning system, credit card transactions, closed-circuit television and medical facility use records) [ 47 , 48 ]. Testing avoidance from fear of stigma [ 46 , 49 ] would likely have affected the early period of the analysis, which strongly reflected the abnormally high spike of cases in Daegu city traced to the local church.…”

Contact tracing and isolation reduces covid-19 incidence in a structured agent-based model

“…[11] Since R t = 1 at the peak of the epidemic and the fraction susceptible at the peak of the epidemic is known for each simulation, R 0 can accordingly be solved numerically. Disease progression: On the day an agent becomes infected with SARS-CoV-2, the model draws from a number of distributions and estimates of risk, based on the published Covid-19 literature, [12,13] to determine (1) whether the agent will become symptomatic and when, (2) when the agent will become infectious, 3whether the agent will be tested and when, (4) whether the agent will stay home and when, (5) whether the agent will require hospitalisation and when, and (6) whether the agent will die and when. The model remains flexible regarding these values -for example to account for hospitals being full.…”

Fixing England’s COVID-19 response: learning from international experience

“…Several countries that have been most successful, such as Japan, South Korea 26 and Uruguay, 27 have focused on investigating clusters through thorough retrospective tracing to identify common sources of infection, recognising the important role played by super-spreading events. This requires a major investment in people on the ground, so-called shoe leather epidemiology.…”