Tracing the Untraceables: A Joint Outbreak Investigation With Law Enforcement Using a Geographic Information System.

The application of geospatial data often allows the tracing of people who are involved in activities of an illegal nature. In June 2021, we estimated the true magnitude of the spread of COVID-19 within the networks of escort-karaoke bars in Seoul, Republic of Korea, using geographic information system (GIS)-based contact tracing that was applied to our epidemiological investigation. Our joint rapid response team, composed of epidemic investigation officers and police personnel, identified 19 paper-traced cases and 158 GIS-traced cases from 5,692 confirmed cases in Seoul during the study period (June to July 2021). Our findings suggest that collaboration with law enforcement agencies and the use of overlaid satellite imagery in outbreak investigations enhances high vigilance and reduces the risk of potential breaches of human rights in the process.

Factors associated with the timely diagnosis of malaria and the utilization of types of healthcare facilities: a retrospective study in the Republic of Korea.

BACKGROUND: This study aimed to analyze trends in the timely diagnosis of malaria cases over the past 10 years in relation to the utilization of different types of healthcare facilities. METHODS: The study included 3,697 confirmed and suspected cases of malaria reported between January 1, 2013, and December 31, 2022, in the national integrative disease and healthcare management system. Some cases lacking a case report or with information missing from the case report were excluded from the analysis. A generalized linear model with a Poisson distribution was constructed to estimate risk ratios and 95% confidence intervals adjusted for other variables, such as distance. RESULTS: When cases involving diagnosis >5 days after symptom onset in confirmed patients (5DD) were examined according to the type of healthcare facility, the risk ratio of 5DD cases was found to be higher for tertiary hospitals than for public health facilities. Specifically, the risk ratio was higher when the diagnosis was established at a tertiary hospital, even after a participant had visited primary or secondary hospitals. In an analysis adjusted for the distance to each participant's healthcare facility, the results did not differ substantially from the results of the crude analysis. CONCLUSION: It is imperative to improve the diagnostic capabilities of public facilities and raise awareness of malaria at primary healthcare facilities for effective prevention and control.

Comparing the effectiveness of bivalent and monovalent COVID-19 vaccines against COVID-19 infection during the winter season of 2022-2023: A real-world retrospective observational matched cohort study in the Republic of Korea.

OBJECTIVES: To compare the effectiveness of bivalent and monovalent COVID-19 vaccines throughout the 2022-2023 winter season based on real-world data. METHODS: This retrospective observational matched cohort study used the national vaccination program and a surveillance dataset from the Republic of Korea, and included adults aged >18 years who received bivalent or monovalent COVID-19 vaccines between October 11, 2022, and December 17, 2022. Cox proportional hazard models were used to estimate the hazard ratio for COVID-19 infection between the groups. RESULTS: We included 29,245 matched individuals in the bivalent and monovalent vaccine groups, respectively. The bivalent vaccine recipients showed 12.2% (95% confidence interval [CI] 6.5-17.7%) additional protection against COVID-19 infection compared with the monovalent vaccine recipients. The additional protection provided by bivalent vaccines was significantly higher among residents of long-term care facilities (39.4%, 95% CI 21.6-53.1%). Maximum additional protection was observed 3 to 4 months after completing the vaccination (17.6%, 95% CI 6.6-27.3%). CONCLUSION: Bivalent COVID-19 vaccines showed significantly better protection against infection than monovalent vaccines among adults during the 2022-2023 winter season. Our results highlight that immunization programs with bivalent vaccines comprising recent variants can be an effective measure to prepare for seasonal COVID-19 circulation.

Estimated impact of the national hepatitis B immunization program on acute viral hepatitis B among adolescents in Republic of Korea.

OBJECTIVES: We aimed to estimate the impact of the national hepatitis B immunization program on the incidence of acute hepatitis B infection among adolescents in South Korea. METHODS: We estimated the counterfactual incidence rate of reported acute hepatitis B among adolescents from 2016 to 2020 compared to the assumption that the national hepatitis B immunization program for children had not been implemented since 1995. The impact of the national hepatitis B immunization program for adolescents was measured by estimating the absolute risk reduction and averted acute hepatitis B infections among adolescents from 2016 to 2020 attributed to the national immunization program. RESULTS: The relative risk reduction of acute hepatitis B among adolescents was estimated to be 83.5% after implementing the national hepatitis B immunization program. The incidence rate of reported acute hepatitis B infections among adolescents decreased from 0.39 to 0.06 per 100,000 person-years, and 43 acute hepatitis B infections, including 17 symptomatic cases, were averted annually from 2016 to 2020 by the national hepatitis B immunization program. CONCLUSION: The national hepatitis B immunization program for children was effective in preventing acute hepatitis B infection among adolescents in South Korea.

Required Elements for an Integrated Biosurveillance Platform: A Capacity and Needs Assessment of the Central Government in the Republic of Korea.

New and reemerging infectious disease outbreaks threaten human safety worldwide, increasing the urgency to implement biosurveillance systems that enhance government capacity in public health emergency preparedness and response. To do so, it is necessary to evaluate existing surveillance and response activities and identify potential barriers at the national level. This study aimed to assess the current status and readiness of government agencies in South Korea, particularly for information sharing and use, and to identify barriers and opportunities in developing an agency-integrated biosurveillance system. The target sample size was 66 government officials, working at 6 relevant government ministries. We invited a total of 100 officials to participate. A total of 34 government officials completed the survey (34.0% response rate), 18 (52.9%) of whom were affiliated with the Korea Disease Control and Prevention Agency or the Ministry of Health and Welfare. Findings revealed that information sharing between government agencies occurred frequently, but a discrepancy existed in terms of the type of information shared and stored. Although information sharing with other agencies and ministries occurred at all stages-prevention, preparation, response, and recovery-it mostly revolved around preventive activities, with no respondents reportedly sharing recovery-related information. An agency-integrated biosurveillance system is crucial in preparing for the next pandemic, as well as supporting information sharing, analysis, and interpretation across humans, animals, and the environment. It is key to national and global health security.

Association between face covering policies and the incidence of coronavirus disease 2019 in European countries.

OBJECTIVES: This study was conducted to determine the impact of the strengthening or relaxation of face covering mandates on the subsequent national case incidence of coronavirus disease 2019 (COVID-19) in Europe as the full vaccination rate was increasing. METHODS: European countries in which case incidence increased for 3 consecutive weeks were monitored and analyzed using COVID-19 incidence data shared by the World Health Organization (WHO). The epidemic trend of COVID-19 in Europe was compared with that of countries elsewhere in the world based on WHO weekly epidemiological reports from June 20 to October 30, 2021. In addition, this study provided insight into the impact of government mask mandates on COVID-19 incidence in Europe by measuring the index scores of those facial covering policies before and after mandate relaxation or strengthening. The effects of the vaccination rate and the speed of vaccination on COVID-19 incidence were also analyzed. RESULTS: The incidence of COVID-19 after the relaxation of face covering mandates was significantly higher than before relaxation. However, no significant difference was observed in vaccination rate between countries with increased and decreased incidence. Instead, rapid vaccination delayed the resurgence in incidence. CONCLUSIONS: The findings suggest that face covering policies in conjunction with rapid vaccination efforts are essential to help mitigate the spread of COVID-19.

Changes in the pattern and disease burden of acute respiratory viral infections before and during the COVID-19 pandemic.

OBJECTIVES: We conducted a comparative analysis of the differences in the incidence of 8 acute respiratory viruses and the changes in their patterns before and during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: Three sentinel surveillance systems of the Korea Disease Control and Prevention Agency and data from the Health Insurance Review and Assessment Service were analyzed. The average numbers of reported cases and the related hospital admissions and outpatient data were compared between April 2018-2019 and 2020-2021. Changes in the disease burden and medical expenditures between these 2 time periods were evaluated. RESULTS: During the COVID-19 pandemic, the number of reported cases of all acute respiratory viral infections, except for human bocavirus, decreased significantly. Data from the Health Insurance Review and Assessment Service also showed decreases in the actual amount of medical service usage and a marked reduction in medical expenditures. CONCLUSION: Non-pharmacological interventions in response to COVID-19 showed preventive effects on the transmission of other respiratory viruses, as well as COVID-19. Although COVID-19 had a tremendous impact on society as a whole, with high social costs, there were also positive effects, such as a reduction in the incidence of acute respiratory viral infections.

Time-series comparison of COVID-19 case fatality rates across 21 countries with adjustment for multiple covariates.

OBJECTIVES: Although it is widely used as a measure for mortality, the case fatality rate (CFR) ofcoronavirus disease 2019 (COVID-19) can vary over time and fluctuate for many reasons otherthan viral characteristics. To compare the CFRs of different countries in equal measure, weestimated comparable CFRs after adjusting for multiple covariates and examined the mainfactors that contributed to variability in the CFRs among 21 countries. METHODS: For statistical analysis, time-series cross-sectional data were collected from OurWorld in Data, CoVariants.org, and GISAID. Biweekly CFRs of COVID-19 were estimated bypooled generalized linear squares regression models for the panel data. Covariates includedthe predominant virus variant, reproduction rate, vaccination, national economic status,hospital beds, diabetes prevalence, and population share of individuals older than age 65. Intotal, 21 countries were eligible for analysis. RESULTS: Adjustment for covariates reduced variation in the CFRs of COVID-19 across countriesand over time. Regression results showed that the dominant spread of the Omicron variant,reproduction rate, and vaccination were associated with lower country-level CFRs, whereasage, the extreme poverty rate, and diabetes prevalence were associated with higher countrylevel CFRs. CONCLUSION: A direct comparison of crude CFRs among countries may be fallacious, especiallyin a cross-sectional analysis. Our study presents an adjusted comparison of CFRs over timefor a more proper comparison. In addition, our findings suggest that comparing CFRs amongdifferent countries without considering their context, such as the epidemic phase, medicalcapacity, surveillance strategy, and socio-demographic traits, should be avoided.

Generic Logic Model for Coronavirus Disease-2019 Responses Based on the South Korean Experience.

BACKGROUND: As the global coronavirus disease-2019 (COVID-19) pandemic continues, many countries have implemented public health policies, such as lockdowns and physical distancing measures, to prevent its spread. South Korea's response to COVID-19, which prevented an increase in confirmed cases and increased resilience, has been considered very effective. PURPOSE: To analyze Korea's response to COVID-19 in 2020 and develop a logic model to evaluate performance effectiveness in follow-up studies. METHODS: By content analysis of Korea Disease Control and Prevention Agency (KDCA) press releases, we defined the problems and identified the causes of the health and social effects of the COVID-19 outbreak. Next, we created a problem tree and developed a logic model that comprised inputs, activities, outputs, outcomes, and impacts. Finally, we held expert consultations to obtain expert opinions regarding the logic model and to ensure the model's validity. RESULTS: South Korea's COVID-19 response policy mitigated the social and health impacts. The 2020 COVID-19 responses had four outcomes (identifying cases on time, preventing transmission of coronavirus infection, effective treatment of COVID-19 cases, protecting public resilience and well-being) and 12 outputs; South Korea conducted 32 activities. CONCLUSION: The results can be a practical reference for managing problems faced in other countries. Korean policy may be of interest in the future for international decision-makers in charge of policy enforcement and those who may be called on to respond to new infectious diseases.

Reconstructing a COVID-19 outbreak within a religious group using social network analysis simulation in Korea.

OBJECTIVES: We reconstructed a coronavirus disease 2019 (COVID-19) outbreak to examine how a large cluster at a church setting spread before being detected and estimate the potential effectiveness of complying with mask-wearing guidelines recommended by the government. METHODS: A mathematical model with a social network analysis (SNA) approach was used to simulate a COVID-19 outbreak. A discrete-time stochastic simulation model was used to simulate the spread of COVID-19 within the Sarang Jeil church. A counterfactual experiment using a calibrated baseline model was conducted to examine the potential benefits of complying with a mask-wearing policy. RESULTS: Simulations estimated a mask-wearing ratio of 67% at the time of the outbreak, which yielded 953.8 (95% confidence interval [CI], 937.3 to 970.4) cases and was most consistent with the confirmed data. The counterfactual experiment with 95% mask-wearing estimated an average of 45.6 (95% CI, 43.4 to 47.9) cases with a standard deviation of 20.1. The result indicated that if the church followed government mask-wearing guidelines properly, the outbreak might have been one-twentieth the size. CONCLUSIONS: SNA is an effective tool for monitoring and controlling outbreaks of COVID-19 and other infectious diseases. Although our results are based on simulations and are thus limited, the precautionary implications of social distancing and mask-wearing are still relevant. Since person-to-person contacts and interactions are unavoidable in social and economic life, it may be beneficial to develop precise measures and guidelines for particular organizations or places that are susceptible to cluster outbreaks.

Dynamics of the COVID-19 epidemic in the post-vaccination period in Korea: a rapid assessment.

OBJECTIVES: Coronavirus disease 2019 (COVID-19) has had a tremendous impact on public health and socioeconomic conditions globally. Although non-pharmaceutical interventions (NPIs) such as social distancing effectively reduced the incidence of COVID-19, especially in Korea, demand for vaccination has increased to minimize the social costs of NPIs. This study estimated the potential benefits of COVID-19 vaccination in Korea. METHODS: A mathematical model with vaccinated-susceptible-latent-infectious-recovered compartments was used to simulate the COVID-19 epidemic. The compartments were stratified into age groups of 0-19 years, 20-59 years, and 60 years or older. Based on the Korea Disease Control and Prevention Agency national vaccination plan for the second quarter of 2021, announced on March 15, we developed vaccination scenarios (with 150,000 dose/d and 100% compliance as the main scenario). Comparing scenarios without vaccination or with higher/lower vaccination rates and compliance, we estimated the numbers of COVID-19 cases that will be prevented by vaccination. RESULTS: The results projected 203,135 cases within a year after April 2021 without vaccination, which would be reduced to 71,248 (64.9% decrease) by vaccination. Supposing a vaccination rate of 150,000 dose/d and 100% compliance, social distancing interventions for those aged 20 or more can be retracted after January 1, 2022. CONCLUSIONS: We expect COVID-19 vaccination to be effective in Korea. Health authorities should minimize delays in vaccination and vaccine avoidance to maximize the effectiveness of vaccination and end social distancing early.

The Evolving Policy Debate on Border Closure in Korea.

OBJECTIVES: In this paper, we aimed to investigate the evolving debate over border closure in Korea during the coronavirus disease 2019 (COVID-19) pandemic, to address the main themes associated with border closure, and to discuss the factors that need to be considered when making such decisions. METHODS: We collated and reviewed previously conducted review studies on border closures during infectious disease outbreaks to derive relevant themes and factors. RESULTS: According to our systematic review on border closures and travel restrictions, the effects of such containment efforts are limited. We suggest considering the following factors when determining whether to impose border closure measures: (1) disease characteristics, (2) timeliness of implementation, (3) transmission delay and the basic reproduction number, (4) globalization and pandemics, and (5) social and economic costs. CONCLUSIONS: Our assessment indicates that the effects of border closures are at best temporary and limited. Alternative measures must be contemplated and implemented to suppress the spread of COVID-19 in particular and infectious diseases more broadly.

Implementation System of a Biosurveillance System in the Republic of Korea and Its Legal Ramifications.

Laws are fundamental tools that regulate and manage various issues to protect the rights of the people in a society. Legislation on disease surveillance enables agencies to regulate and manage public health, including preventing the spread of infectious diseases. We assessed the Infectious Disease Prevention and Control Act of Korea (IDPCA) through the lens of biosurveillance to understand its effectiveness in protecting public health. In addition, the relevant legislation and regulations of the United States and the World Health Organization were examined. The evaluation concludes that the current IDPCA is limited in terms of providing guidance for early detection of and response to hazards using integrated data and an information-sharing system. Further revision of the laws is needed to enable early detection and warning of potential threats to public health.

Estimating the medical capacity required to administer mass prophylaxis: a hypothetical outbreak of smallpox virus infection in Korea.

OBJECTIVES: The aim of this study was to estimate the medical surge capacity required for mass prophylaxis based on a hypothetical outbreak of smallpox. METHODS: We performed a simulation using the Bioterrorism and Epidemic Outbreak Response Model and varied some important parameters, such as the number of core medical personnel and the number of dispensing clinics. RESULTS: Gaps were identified in the medical surge capacity of the Korean government, especially in the number of medical personnel who could respond to the need for mass prophylaxis against smallpox. CONCLUSIONS: The Korean government will need to train 1,000 or more medical personnel for such an event, and will need to prepare many more dispensing centers than are currently available.

Enhancing 'Whole-of-Government' Response to Biological Events in Korea: Able Response 2014.

Since 2011, the Republic of Korea (ROK) and United States (U.S.) have been collaborating to conduct inter- and intra-governmental exercises to jointly respond to biological events in Korea. These exercises highlight U.S. interest in increasing its global biosurveillance capability and the ROK's interest in improving cooperation among ministries to respond to crises. With Able Response (AR) exercises, the ROK and U.S. have improved coordination among US and ROK government and defense agencies responding to potential bio-threats and identified additional areas on which to apply refinements in policies and practices. In 2014, the AR exercise employed a Biosurveillance Portal (BSP) to facilitate more effective communication among participating agencies and countries including Australia. In the present paper, we seek to provide a comprehensive assessment of the AR 2014 (AR14) exercise and make recommendations for future improvements. Incorporating a more realistic response in future scenarios by integrating a tactical response episode in the exercise is recommended.

Syndromic Surveillance System for Korea-US Joint Biosurveillance Portal: Design and Lessons Learned.

Driven by the growing importance of situational awareness of bioterrorism threats, the Republic of Korea (ROK) and the United States have constructed a joint military capability, called the Biosurveillance Portal (BSP), to enhance biosecurity. As one component of the BSP, we developed the Military Active Real-time Syndromic Surveillance (MARSS) system to detect and track natural and deliberate disease outbreaks. This article describes the ROK military health data infrastructure and explains how syndromic data are derived and made available to epidemiologists. Queries corresponding to 8 syndromes, based on published clinical effects of weaponized pathogens, were used to classify military hospital patient records to form aggregated daily syndromic counts. A set of ICD-10 codes for each syndrome was defined through literature review and expert panel discussion. A study set of time series of national daily counts for each syndrome was extracted from the Defense Medical Statistical Information System between January 1, 2011, and May 31, 2014. A stratified, adjusted cumulative summation algorithm was implemented for each syndrome group to signal alerts prompting investigation. The algorithm was developed by calculating sensitivity to sets of 1,000 artificial outbreak signals randomly injected in the dataset, with each signal injected in a separate trial. Queries and visualizations were adapted from the Suite for Automated Global bioSurveillance. Findings indicated that early warning of outbreaks affecting fewer than 50 patients will require analysis at subnational levels, especially for common syndrome groups. Developing MARSS to improve sensitivity will require modification of underlying syndromic diagnosis codes, engineering to coordinate alerts among subdivisions, and enhanced algorithms. The bioterrorist threat in the Korean peninsula mandates these efforts.

Impact of differential injury reporting on the estimation of the total number of work-related amputations.

BACKGROUND: A capture-recapture analysis was performed to estimate the total number of work-related amputations. We examined the impact of misclassification due to differential injury reporting on the estimate of total number of work-related amputations. METHODS: Bureau of Labor Statistics' Survey of Occupational Injuries and Illnesses (SOII) samples and workers' compensation records (WC) were used to estimate the total number of work-related amputations. Some of the amputation cases in one data source matched with injuries other than amputations in the other data source. We performed sensitivity analyses reassigning such cases as matched amputations. RESULTS: Depending on how we treated the cases matched with other injuries, the total number of work-related amputations ranged from 276 to 442 cases, yielding dramatically different capture rates (35-87%). CONCLUSION: Due to differential classification, estimates of work-related amputations would be biased. Our findings highlight the importance of accurately reporting and classifying work-related injuries and illnesses.

Prevalence of musculoskeletal symptoms among agricultural workers in the United States: an analysis of the National Health Interview Survey, 2004-2008.

Ergonomic risks from agricultural tasks can compromise musculoskeletal health of workers. This study estimated prevalence of musculoskeletal symptoms in a sample representing almost 2 million US agricultural industry workers. This study used National Health Interview Survey data from 2004 to 2008. Weighted prevalence was calculated by demographic and employment factors. Prevalence ratios were calculated using generalized linear models with the Poisson distribution assumption. Prevalence rates of low back and neck pain in the previous 3 months were 24.3% and 10.5%, respectively, among agricultural workers. Monthly prevalence of joint pain was 17.0% for hips/knees, 9.8% for shoulders, 9.5% for wrists/hands, 5.4% for elbows, and 4.7% for ankles/toes. Agricultural workers had a significantly higher prevalence of shoulder pain than all other industry workers (prevalence ratios [PR] = 1.28, 95% confidence interval [CI]: 1.02-1.61). This study provides detailed national estimates of musculoskeletal symptom prevalence to understand the burden and the need for intervention among agricultural workers.

Use of multiple data sources for surveillance of work-related amputations in Massachusetts, comparison with official estimates and implications for national surveillance.

BACKGROUND: Accurate surveillance of work-related injuries is needed at national and state levels. We used multiple sources for surveillance of work-related amputations, compared findings with Survey of Occupational Injuries and Illnesses (SOII) estimates, and assessed generalizability to national surveillance. METHODS: Three data sources were used to enumerate work-related amputations in Massachusetts, 2007-2008. SOII eligible amputations were compared with SOII estimates. RESULTS: 787 amputations were enumerated, 52% ascertained through hospital records only, exceeding the SOII estimate (n = 210). The estimated SOII undercount was 48% (95% CI: 36-61%). Additional amputations were reported in SOII as other injuries, accounting for about half the undercount. Proportionately more SOII estimated than multisource cases were in manufacturing and fewer in smaller establishments. CONCLUSION: Multisource surveillance enhanced our ability to document work-related amputations in Massachusetts. While not feasible to implement for work-related conditions nationwide, it is useful in states. Better understanding of potential biases in SOII is needed.