"Don't Know When or Where Infected" 3 out of 10 People... Highest Level After Onset

COVID-19 Central Disease Control Headquarters, 30.7% of Cases Under Investigation Confirmed
"Infections Spreading Throughout Communities"...Limitations of Epidemiological Investigations

As the spread of COVID-19 continues, the number of new confirmed cases remained in the 1,300s for the third consecutive day on the 11th. Citizens are waiting for testing at a temporary screening clinic set up in front of Exit 6 of Samseong Station in Gangnam-gu, Seoul. Photo by Mun Ho-nam munonam@

[Asia Economy Reporter Choi Dae-yeol] About 3 out of 10 patients newly diagnosed with COVID-19 in the past two weeks were unable to identify their infection routes. This is the highest level since the quarantine authorities began separately tracking related statistics in April last year. As the fourth wave of the pandemic intensifies, it appears that field epidemiological investigations are struggling to keep up with the spread.

According to the Central Disease Control Headquarters' analysis of infection routes for newly confirmed cases over the recent two weeks (June 28 to July 11), among 12,975 confirmed cases during this period, 3,981 cases (30.7%) were still under investigation. This figure had approached 30% in late April but decreased as the spread subsided, only to surge again as daily new cases exceeded 1,000 for several consecutive days recently.

When a cluster infection of a certain scale or larger spreads, the index patient who was first confirmed is classified as a 'case under investigation,' while the remaining confirmed cases within the same cluster are categorized as regional cluster outbreaks or contacts of preceding confirmed cases. A high number of cases under investigation indicates that cluster infections with unknown initial sources are spreading throughout the community. In Seoul, where the number of new confirmed cases is the highest, cases under investigation approached half.

On the 11th, one day before the implementation of Level 4 social distancing in the Seoul metropolitan area, an official is posting a notice at a restaurant in Seoul city stating "No entry for groups of 5 or more before 6 PM, no entry for groups of 3 or more after 6 PM." Photo by Mun Ho-nam munonam@

Nearly half (46.6%) of recent new confirmed cases were infected through contact with preceding confirmed cases. Regional cluster outbreaks accounted for 16.7%, and overseas inflow cases made up 5.6%. Hospitals and nursing hospitals accounted for 0.3%, and overseas inflow-related new confirmed cases were 0.1%.

According to the quarantine authorities, new cluster infections are emerging daily. Since the first confirmed case at a middle school in Yongsan-gu, Seoul, on the 3rd, a total of 10 people including other students, family members, and staff have tested positive. At a protective gear manufacturing company in Hanam-si, Gyeonggi Province, after one employee was first confirmed on the 7th, additional infections among other employees and their families have occurred, increasing the cumulative confirmed cases to 17.

New cluster infections or additional cases have been confirmed in places where masks are likely not worn consistently, such as a pub in Seo-gu, Incheon (37 cases), a pub in Hwaseong-si (17 cases), a pub in Gunsan-si, Jeonbuk (17 cases), a general pub in Jung-gu, Daegu (28 cases), and entertainment establishments in Gimhae, Gyeongnam (37 cases).

This content was produced with the assistance of AI translation services.