Latent Tuberculosis Infection Screening and Treatment in Congregate Settings (TB FREE COREA): Demographic Profiles of Interferon-Gamma Release Assay Cohort.

In 2017, the Korean government launched an unprecedentedly large-scaled latent tuberculosis infection (LTBI) screening project which covered more than a million individuals in congregate settings. A total of 1,047,689 participants of source population (n = 2,336,157) underwent LTBI testing from 2017 to 2018. The overall LTBI test uptake rate during this project was 44.8%. Workers in daycare centers (83.5%) and kindergartens (78.9%) showed high participation rate. A total of 1,012,206 individuals with valid results of interferon-gamma release assay (IGRA) were selected to constitute the IGRA cohort. Most of the enrolled participants in the IGRA cohort were in their working age. Approximately, three-quarters of total enrolled population were female. Investigating the LTBI prevalence, stages of LTBI care cascade, natural history of LTBI, efficacy of LTBI treatment and cost-effectiveness of LTBI screening are feasible within this IGRA cohort.

Impact of Media Coverage on Influenza Vaccine Coverage in Elderly Individuals from 2020 to 2021 in the Republic of Korea.

Increased awareness of adverse events following immunization (AEFI) can disrupt vaccination programs. In South Korea, a report of alleged influenza vaccine-related deaths attracted significant media attention in 2020. We retrieved the vaccination coverage and AEFI data to determine their association with media coverage. Between 2015 and 2019, the vaccination coverage rate ranged between 80.5% and 83.3%; however, the vaccination coverage rate declined significantly from 2020 to 2021 to 73.6% (p < 0.0001). During the 43rd week of 2020, following a large amount of media coverage on vaccine safety issues, the number of cases with AEFI reached 60. Between 2015 and 2020, the mortality rate ratios for influenza vaccines and non-vaccines ranged between 0.1296 (95% confidence interval (CI), 0.1262-0.1331, p < 0.0001) and 0.1608 (95% CI, 0.1572-0.1644, p < 0.0001). Vaccine safety surveillance should be continued in conjunction with investigation and transparent risk communication to maintain public trust in vaccines and vaccinations.

Epidemiological Characteristics of COVID-19 Outbreak at Fitness Centers in Cheonan, Korea.

BACKGROUND: In February 2020, a coronavirus disease 2019 (COVID-19) outbreak was reported in fitness centers in Cheonan, Korea. METHODS: From February 24 to March 13, an epidemiological investigation was conducted on the fitness center outbreak. All those who were screened were tested for severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) using real-time reverse transcriptase polymerase chain reaction. Contacts were traced and self-isolated for 14 days. We determined the epidemiological characteristics of confirmed cases of SARS-CoV-2 infection, and estimated the time-dependent reproduction number to assess the transmission dynamics of the infection. RESULTS: A total of 116 cases were confirmed, and 1,687 contacts were traced. The source cases were 8 Zumba instructors who led aerobics classes in 10 fitness centers, and had the largest average number of contacts. A total of 57 Zumba class participants, 37 of their family members, and 14 other contacts were confirmed as cases. The attack rate was 7.3%. The contacts at Zumba classes and homes had a higher attack rate than other contacts. The mean serial interval (± standard deviation) were estimated to be 5.2 (± 3.8) days. The time-dependent reproduction number was estimated to be 6.1 at the beginning of the outbreak, but it dropped to less than 1, 2 days after the epidemiological investigation was launched. CONCLUSION: The results suggest that the COVID-19 outbreak was effectively contained with rigorous contact tracing, isolating, and testing in combination with social distancing without a lock-down.

The Korean Influenza National Immunization Program: History and Present Status.

The Korean influenza national immunization program was first established as an interim program in 1997, administering the influenza vaccine to low-income elderly adults. In 2005, the program assumed its present form of providing free influenza vaccination to adults aged ≥65 years. After turning over the influenza vaccination for elderly adults to the private sectors in 2015, the influenza vaccination coverage rate among this population increased to >80%. In addition, after the 2009 H1N1 influenza epidemic crisis, the vaccine was domestically produced. By reaching a 75% vaccination coverage rate in the target groups, it was possible to put an end to the influenza pandemic and fix the shortcomings of the system that existed at that time. The influenza vaccination program, provided free of cost, was extended to include infants aged <12 months in 2016 and ≤59 months in 2017 in order to reduce the influenza burden in these populations. However, the vaccine effectiveness remains low despite the high vaccination rates in elderly adults. Therefore, several areas, such as the adoption of quadrivalent influenza vaccine, adjuvanted influenza vaccine, and high-dose influenza vaccine and the expansion of vaccination target groups, still need to be addressed.

Prevalence of Spirometrically-defined Restrictive Ventilatory Defect in Korea: The Fourth-2, 3, and Fifth Korean National Health and Nutrition Examination Survey, 2008-2012.

The aim of the study was to evaluate the prevalence of restrictive ventilatory defect and to determine the risk factors in subjects with spirometrically-defined restrictive ventilatory defect. We used the population-based, fourth-2, 3 (2008, 2009) and fifth (2010-2012) Korea National Health and Nutrition Examination Survey (KNHANES) to analyze 15,073 subjects, aged ≥40 yr who underwent spirometry. Chest radiographs were also analyzed to identify restrictive lung disease. Spirometrically-defined restrictive ventilatory defect (FEV1/FVC≥70% and FVC<80% of mean predicted value) was detected in 11.3% (n= 1,709) of subjects aged ≥40 yr. The prevalence increased to 12.3% on using the lower limit of normal (LLN) criteria. Approximately 99.4% of subjects were classified as mild restrictive. Among these, 11.3% had inactive tuberculosis (TB) lesion, 2.2% cardiac disease, 2.0% previous operation scar or radiation injury and/or mediastinal disease, and 7.4% other pulmonary disease suggestive of restrictive lung diseases on chest radiograph. Evidence of previous TB history was independently associated with restrictive ventilatory defect (odds ratios [OR], 1.78; 95% confidence interval, 1.45-2.18) after adjustment for gender, age, smoking, area for residence and body mass index. The prevalence of restrictive ventilatory defect among the nationwide population in Korea was 11.3% with fixed ratio criterion and 12.3% with LLN criterion. Most cases were of the mild restrictive category and previous TB history is the independent risk factor for restrictive ventilatory defect.

Data resource profile: the Korea National Health and Nutrition Examination Survey (KNHANES).

The Korea National Health and Nutrition Examination Survey (KNHANES) is a national surveillance system that has been assessing the health and nutritional status of Koreans since 1998. Based on the National Health Promotion Act, the surveys have been conducted by the Korea Centers for Disease Control and Prevention (KCDC). This nationally representative cross-sectional survey includes approximately 10 000 individuals each year as a survey sample and collects information on socioeconomic status, health-related behaviours, quality of life, healthcare utilization, anthropometric measures, biochemical and clinical profiles for non-communicable diseases and dietary intakes with three component surveys: health interview, health examination and nutrition survey. The health interview and health examination are conducted by trained staff members, including physicians, medical technicians and health interviewers, at a mobile examination centre, and dieticians' visits to the homes of the study participants are followed up. KNHANES provides statistics for health-related policies in Korea, which also serve as the research infrastructure for studies on risk factors and diseases by supporting over 500 publications. KCDC has also supported researchers in Korea by providing annual workshops for data users. KCDC has published the Korea Health Statistics each year, and microdata are publicly available through the KNHANES website (http://knhanes.cdc.go.kr).