1.Children with COVID-19 after Reopening of Schools, South Korea
Eun Young KIM ; Boyeong RYU ; Eun Kyoung KIM ; Young-Joon PARK ; Young June CHOE ; Hye Kyung PARK ; Eun Kyeong JEONG
Pediatric Infection & Vaccine 2020;27(3):180-183
Purpose:
To describe pediatric coronavirus disease 2019 (COVID-19) cases after the reopening of schools in the Republic of Korea and their transmission routes.
Methods:
All case report forms and epidemiologic investigation forms for children aged 3–18 years reported as COVID-19 cases to the National Notifiable Disease Surveillance System from May 1 to July 12, 2020, were reviewed.
Results:
After the schools were reopened in May 2020, a total of 127 pediatric COVID-19 cases were confirmed until July 12. Of these, 59 children (46%) were exposed to severe acute respiratory syndrome coronavirus 2 through family and relatives, followed by 18 children (14%) through cram schools or private lessons, 8 children (6%) through multi-use facilities, and 3 children (2%) through school.
Conclusions
The present data do not suggest an increased risk of COVID-19 transmission in the context of stringent school-based infection prevention measures introduced across the country.
2.Children with COVID-19 after Reopening of Schools, South Korea
Eun Young KIM ; Boyeong RYU ; Eun Kyoung KIM ; Young-Joon PARK ; Young June CHOE ; Hye Kyung PARK ; Eun Kyeong JEONG
Pediatric Infection & Vaccine 2020;27(3):180-183
Purpose:
To describe pediatric coronavirus disease 2019 (COVID-19) cases after the reopening of schools in the Republic of Korea and their transmission routes.
Methods:
All case report forms and epidemiologic investigation forms for children aged 3–18 years reported as COVID-19 cases to the National Notifiable Disease Surveillance System from May 1 to July 12, 2020, were reviewed.
Results:
After the schools were reopened in May 2020, a total of 127 pediatric COVID-19 cases were confirmed until July 12. Of these, 59 children (46%) were exposed to severe acute respiratory syndrome coronavirus 2 through family and relatives, followed by 18 children (14%) through cram schools or private lessons, 8 children (6%) through multi-use facilities, and 3 children (2%) through school.
Conclusions
The present data do not suggest an increased risk of COVID-19 transmission in the context of stringent school-based infection prevention measures introduced across the country.
3.Age-Stratified Risk of Severe COVID-19 for People With Disabilities in Korea:Nationwide Study Considering Disability Type
Boyeong RYU ; Hoyeon JANG ; Jaiyong KIM ; Sung-il CHO ; Seong-Sun KIM
Journal of Korean Medical Science 2025;40(7):e37-
Background:
Understanding disparities in severe coronavirus disease 2019 (COVID-19) outcomes between people with disabilities (PwD) and people without disabilities (PwoD) is crucial, particularly when considering the heterogeneity within PwD and age differences.This study aimed to compare severe COVID-19 outcomes including deaths between PwD and PwoD with analyses stratified by age group and further examined by disability type.
Methods:
This retrospective, population-based cohort study used linked data from national COVID-19 cases and health insurance for individuals aged ≥ 19 years with COVID-19 from January 2020 to October 2022 in the Republic of Korea. Severe outcomes included severe cases and deaths, with logistic regression analysis of the risk disparities between PwD and PwoD based on age group and disability types. The subgroup analysis considered epidemic periods, accounting for the severe acute respiratory syndrome coronavirus 2 variant circulation.
Results:
The risk of severe COVID-19 outcomes and deaths among PwD varied by age and disability type. While severe outcomes were most prevalent in the older age groups for both PwD and PwoD, younger PwD faced a markedly higher risk—up to eightfold—compared to PwoD. The risk of disability status was greater than that of comorbidities in the 19–39 age group. Among disability types, individuals with internal organs-related and intellectual disabilities showed higher risk disparities with PwoD in severe outcomes than other types of disabilities. Throughout the pandemic, the disparity in death risk remained similar, with a slight increase in disparity during the omicron period for all severe outcomes in the age groups 19–39 and 40–64 years.
Conclusion
Prioritizing younger PwD, along with older age groups and people with comorbidities, is crucial in addressing public health crises. Risk-based prioritization is important to reduce overall risk. This includes prioritizing people with nternal organs-related and intellectural disabilities, who face higher health risks among PwD during a pandemic when resources are limited and time is of the essence.
4.Age-Stratified Risk of Severe COVID-19 for People With Disabilities in Korea:Nationwide Study Considering Disability Type
Boyeong RYU ; Hoyeon JANG ; Jaiyong KIM ; Sung-il CHO ; Seong-Sun KIM
Journal of Korean Medical Science 2025;40(7):e37-
Background:
Understanding disparities in severe coronavirus disease 2019 (COVID-19) outcomes between people with disabilities (PwD) and people without disabilities (PwoD) is crucial, particularly when considering the heterogeneity within PwD and age differences.This study aimed to compare severe COVID-19 outcomes including deaths between PwD and PwoD with analyses stratified by age group and further examined by disability type.
Methods:
This retrospective, population-based cohort study used linked data from national COVID-19 cases and health insurance for individuals aged ≥ 19 years with COVID-19 from January 2020 to October 2022 in the Republic of Korea. Severe outcomes included severe cases and deaths, with logistic regression analysis of the risk disparities between PwD and PwoD based on age group and disability types. The subgroup analysis considered epidemic periods, accounting for the severe acute respiratory syndrome coronavirus 2 variant circulation.
Results:
The risk of severe COVID-19 outcomes and deaths among PwD varied by age and disability type. While severe outcomes were most prevalent in the older age groups for both PwD and PwoD, younger PwD faced a markedly higher risk—up to eightfold—compared to PwoD. The risk of disability status was greater than that of comorbidities in the 19–39 age group. Among disability types, individuals with internal organs-related and intellectual disabilities showed higher risk disparities with PwoD in severe outcomes than other types of disabilities. Throughout the pandemic, the disparity in death risk remained similar, with a slight increase in disparity during the omicron period for all severe outcomes in the age groups 19–39 and 40–64 years.
Conclusion
Prioritizing younger PwD, along with older age groups and people with comorbidities, is crucial in addressing public health crises. Risk-based prioritization is important to reduce overall risk. This includes prioritizing people with nternal organs-related and intellectural disabilities, who face higher health risks among PwD during a pandemic when resources are limited and time is of the essence.
5.Age-Stratified Risk of Severe COVID-19 for People With Disabilities in Korea:Nationwide Study Considering Disability Type
Boyeong RYU ; Hoyeon JANG ; Jaiyong KIM ; Sung-il CHO ; Seong-Sun KIM
Journal of Korean Medical Science 2025;40(7):e37-
Background:
Understanding disparities in severe coronavirus disease 2019 (COVID-19) outcomes between people with disabilities (PwD) and people without disabilities (PwoD) is crucial, particularly when considering the heterogeneity within PwD and age differences.This study aimed to compare severe COVID-19 outcomes including deaths between PwD and PwoD with analyses stratified by age group and further examined by disability type.
Methods:
This retrospective, population-based cohort study used linked data from national COVID-19 cases and health insurance for individuals aged ≥ 19 years with COVID-19 from January 2020 to October 2022 in the Republic of Korea. Severe outcomes included severe cases and deaths, with logistic regression analysis of the risk disparities between PwD and PwoD based on age group and disability types. The subgroup analysis considered epidemic periods, accounting for the severe acute respiratory syndrome coronavirus 2 variant circulation.
Results:
The risk of severe COVID-19 outcomes and deaths among PwD varied by age and disability type. While severe outcomes were most prevalent in the older age groups for both PwD and PwoD, younger PwD faced a markedly higher risk—up to eightfold—compared to PwoD. The risk of disability status was greater than that of comorbidities in the 19–39 age group. Among disability types, individuals with internal organs-related and intellectual disabilities showed higher risk disparities with PwoD in severe outcomes than other types of disabilities. Throughout the pandemic, the disparity in death risk remained similar, with a slight increase in disparity during the omicron period for all severe outcomes in the age groups 19–39 and 40–64 years.
Conclusion
Prioritizing younger PwD, along with older age groups and people with comorbidities, is crucial in addressing public health crises. Risk-based prioritization is important to reduce overall risk. This includes prioritizing people with nternal organs-related and intellectural disabilities, who face higher health risks among PwD during a pandemic when resources are limited and time is of the essence.
6.Age-Stratified Risk of Severe COVID-19 for People With Disabilities in Korea:Nationwide Study Considering Disability Type
Boyeong RYU ; Hoyeon JANG ; Jaiyong KIM ; Sung-il CHO ; Seong-Sun KIM
Journal of Korean Medical Science 2025;40(7):e37-
Background:
Understanding disparities in severe coronavirus disease 2019 (COVID-19) outcomes between people with disabilities (PwD) and people without disabilities (PwoD) is crucial, particularly when considering the heterogeneity within PwD and age differences.This study aimed to compare severe COVID-19 outcomes including deaths between PwD and PwoD with analyses stratified by age group and further examined by disability type.
Methods:
This retrospective, population-based cohort study used linked data from national COVID-19 cases and health insurance for individuals aged ≥ 19 years with COVID-19 from January 2020 to October 2022 in the Republic of Korea. Severe outcomes included severe cases and deaths, with logistic regression analysis of the risk disparities between PwD and PwoD based on age group and disability types. The subgroup analysis considered epidemic periods, accounting for the severe acute respiratory syndrome coronavirus 2 variant circulation.
Results:
The risk of severe COVID-19 outcomes and deaths among PwD varied by age and disability type. While severe outcomes were most prevalent in the older age groups for both PwD and PwoD, younger PwD faced a markedly higher risk—up to eightfold—compared to PwoD. The risk of disability status was greater than that of comorbidities in the 19–39 age group. Among disability types, individuals with internal organs-related and intellectual disabilities showed higher risk disparities with PwoD in severe outcomes than other types of disabilities. Throughout the pandemic, the disparity in death risk remained similar, with a slight increase in disparity during the omicron period for all severe outcomes in the age groups 19–39 and 40–64 years.
Conclusion
Prioritizing younger PwD, along with older age groups and people with comorbidities, is crucial in addressing public health crises. Risk-based prioritization is important to reduce overall risk. This includes prioritizing people with nternal organs-related and intellectural disabilities, who face higher health risks among PwD during a pandemic when resources are limited and time is of the essence.
7.Risk Factors for Sudden Death Within 2 Days After Diagnosis of COVID-19 in Korea
So Young CHOI ; Boyeong RYU ; Hyun-Ju LEE ; Dong-Hwii KIM ; Eunjeong SHIN ; Seong-Sun KIM ; Donghyok KWON
Journal of Korean Medical Science 2023;38(27):e214-
Background:
We aimed to analyze the risk factors for sudden death after diagnosis of coronavirus disease 2019 (COVID-19) in South Korea and to provide evidence for informing prevention and control interventions for patients at risk of sudden death.
Methods:
We included 30,302 COVID-19 related deaths registered in the patient management information system (Central Disease Control Headquarters) between January 1, 2021, and December 15, 2022. We collected their epidemiological data recorded by the reporting city, province, or country. We performed multivariate logistic regression analysis to identify risk factors for sudden death after diagnosis of COVID-19.
Results:
Among the 30,302 deaths, there were 7,258 (24.0%) and 23,044 (76.0%) sudden and non-sudden deaths, respectively. Sudden death means a person who died within 2 days of diagnosis and who did not receive inpatient treatment. Underlying condition, vaccination status, and place of death were significantly associated with the survival period in all age groups. Moreover, region, sex, and prescription were significantly associated with the survival period only in certain age groups. However, reinfection was not significantly associated with the survival period in any age group.
Conclusion
To our knowledge, this is the first study on the risk factors for sudden death after a diagnosis of COVID-19, which included age, underlying condition, vaccination status, and place of death. Additionally, individuals aged < 60 years without an underlying condition were at high risk for sudden death. However, this group has relatively low interest in health, as can be seen from the high non-vaccination rate (16.1% of the general population vs. 61.6% of the corresponding group). Therefore, there is a possibility for the presence of an uncontrolled underlying disease in this population. In addition, many sudden deaths occurred due to delayed hospital visits to continue economic activities even after the onset of COVID-19 symptoms (7 days overall vs. 10 days average for the group). In conclusion, ‘continued interest in health’ is a key factor in avoiding sudden death in the economically active group (under 60 years of age).
8.Risk factors for deaths associated with COVID-19 according to the cause of death classification in Republic of Korea
Na-Young KIM ; Seong-Sun KIM ; Hyun Ju LEE ; Dong Hwi KIM ; Boyeong RYU ; Eunjeong SHIN ; Donghyok KWON
Osong Public Health and Research Perspectives 2023;14(2):89-99
Objectives:
This study aimed to classify coronavirus disease 2019 (COVID-19)-related deaths according to whether COVID-19 was listed as the cause of death, and to investigate thedifferences in demographic characteristics and risk factors for COVID-19 death classifications.
Methods:
A total of 5,625 deaths in South Korea among patients with confirmed COVID-19 from January 20, 2020 to December 31, 2021 were selected. Excluding false reports and unnatural deaths, 5,597 deaths were analyzed. Based on death report data, deaths were classified according to whether the cause of death was listed as COVID-19 (CD) or not (NCD). The epidemiological characteristics and causes of deaths were investigated using descriptive, univariate, and multivariate statistical analyses. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to analyze the risk factors.
Results:
The case fatality ratio was 0.89% and increased with age. Additionally, 96.4% of the subjects had an underlying disease, and 53.4% died in winter. The proportion of NCDs was 9.3%, of whom 19.1% died at home and 39.0% were confirmed to have COVID-19 after death. Malignant neoplasms (102/416 vs. 637/4,442; OR, 1.71; 95% CI, 1.36−2.16; p < 0.001) were significantly associated with NCD.
Conclusion
This is the first study to analyze risk factors by cause of death using COVID-19death report data in South Korea. These results are expected to be used as evidence forestablishing a death monitoring system that can collect timely information in a new infectiousdisease pandemic.
9.Characteristics and trends of severe/critical COVID-19cases in the Republic of Korea (January 2020 to August 2023)
Se-Jin JEONG ; Shin Young PARK ; Boyeong RYU ; Misuk AN ; Jin-Hwan JEON ; So Young CHOI ; Seong-Sun KIM
Osong Public Health and Research Perspectives 2025;16(1):81-88
Objectives:
We analyzed the demographic and clinical characteristics of patients diagnosedwith coronavirus disease 2019 (COVID-19), focusing specifically on severe/critical cases, andassessed the trends and rates of severity and fatality among these patients in the Republic of Korea.
Methods:
Clinical data on patients with COVID-19 from January 20, 2020 to August 30, 2023were collected from the Korea Disease Control and Prevention Agency’s database. We identified patients who progressed to severe/critical conditions and analyzed their demographic and clinical profiles. Severity and fatality rates were calculated and compared annually to track thedisease progression over time.
Results:
During the surveillance period, 34,572,554 COVID-19 cases were confirmed, among whom 38,112 (0.11%) progressed to severe/critical conditions. Most severe/critical cases occurred in individuals aged ≥60 years, with a notable increase in patients aged ≥80 years from 2022.The overall severity rate was 0.19%, with a fatality rate of 0.10%. However, the severity of cases gradually diminished during the study period. In 2022, the severity and fatality rates decreased to 0.14% and 0.09%, respectively. In 2023, while the severity rate remained stable at 0.15%, thefatality rate further decreased to 0.06%. Notably, throughout the study period, individuals aged ≥80 years had a significantly higher severity rate (2.44%), with a fatality rate of 1.75%.
Conclusion
These findings underscore the importance of prioritizing protection and management strategies for older adults and high-risk groups to mitigate the impact ofCOVID-19. Continued surveillance and analysis are essential to effectively control COVID-19 and minimize its burden on public health.
10.Characteristics and trends of severe/critical COVID-19cases in the Republic of Korea (January 2020 to August 2023)
Se-Jin JEONG ; Shin Young PARK ; Boyeong RYU ; Misuk AN ; Jin-Hwan JEON ; So Young CHOI ; Seong-Sun KIM
Osong Public Health and Research Perspectives 2025;16(1):81-88
Objectives:
We analyzed the demographic and clinical characteristics of patients diagnosedwith coronavirus disease 2019 (COVID-19), focusing specifically on severe/critical cases, andassessed the trends and rates of severity and fatality among these patients in the Republic of Korea.
Methods:
Clinical data on patients with COVID-19 from January 20, 2020 to August 30, 2023were collected from the Korea Disease Control and Prevention Agency’s database. We identified patients who progressed to severe/critical conditions and analyzed their demographic and clinical profiles. Severity and fatality rates were calculated and compared annually to track thedisease progression over time.
Results:
During the surveillance period, 34,572,554 COVID-19 cases were confirmed, among whom 38,112 (0.11%) progressed to severe/critical conditions. Most severe/critical cases occurred in individuals aged ≥60 years, with a notable increase in patients aged ≥80 years from 2022.The overall severity rate was 0.19%, with a fatality rate of 0.10%. However, the severity of cases gradually diminished during the study period. In 2022, the severity and fatality rates decreased to 0.14% and 0.09%, respectively. In 2023, while the severity rate remained stable at 0.15%, thefatality rate further decreased to 0.06%. Notably, throughout the study period, individuals aged ≥80 years had a significantly higher severity rate (2.44%), with a fatality rate of 1.75%.
Conclusion
These findings underscore the importance of prioritizing protection and management strategies for older adults and high-risk groups to mitigate the impact ofCOVID-19. Continued surveillance and analysis are essential to effectively control COVID-19 and minimize its burden on public health.