Vaccine effectiveness and the epidemiological characteristics of a COVID-19 outbreak in a tertiary hospital in Republic of Korea.

BACKGROUND: Healthcare facilities are high-risk sites for infection. This study analyzed the epidemiological characteristics of a coronavirus disease 2019 (COVID-19) outbreak in a tertiary hospital after COVID-19 vaccination had been introduced in Republic of Korea. Vaccine effectiveness (VE) and shared anti-infection strategies are also assessed. METHODS: The risk levels for 4,074 contacts were evaluated. The epidemiological characteristics of confirmed cases were evaluated using the chi-square test. The "1 minus relative risk" method was used to determine VE in preventing infection, progression to severe disease, and death. In the largest affected area (the 8th floor), a separate relative risk analysis was conducted. A multivariate logistic regression analysis (with 95% confidence interval [CIs]) was used to identify transmission risk factors with a significance level <10% via the backward elimination method. RESULTS: In total, 181 cases of COVID-19 were confirmed, with an attack rate of 4.4%. Of those cases, 12.7% progressed to severe disease, and 8.3% died. In the cohort isolation area on the 8th floor, where 79.0% of the confirmed cases occurred, the adjusted odds ratio was 6.55 (95% CI, 2.99-14.33) and 2.19 (95% CI, 1.24-3.88) for caregivers and the unvaccinated group, respectively. VE analysis revealed that 85.8% of the cases that progressed to severe disease and 78.6% of the deaths could be prevented by administering a second vaccine. CONCLUSION: Caregiver training for infection prevention and control is necessary to reduce infection risk. Vaccination is an important intervention to reduce the risk of progression to severe disease and death.

Risk factors for COVID-19 outbreaks in livestock slaughtering and processing facilities in Republic of Korea.

BACKGROUND: The goal of this study was to help prevent and control the spread of coronavirus disease 2019 (COVID-19) by identifying transmission routes and risk factors in livestock slaughtering and processing facilities (SPFs) and establishing an optimal intervention strategy for outbreaks. METHODS: This case series study was a demographic analysis of patients with confirmed COVID-19 associated with 5 SPFs in Korea between January and June 2021. Additionally, in a retrospective cohort study, the association between COVID-19 infection and risk factors was analyzed for SPFs at which outbreaks occurred. RESULTS: The COVID-19 attack rates were 11.2%, 24.5%, and 6.8% at 3 poultry SPFs (PSPFs) and 15.5% and 25.2% at 2 mammal SPFs (MSPFs). Regarding spatial risk factors, the COVID-19 risk levels were 12.1-, 5.2-, and 5.0-fold higher in the refrigeration/ freezing, by-product processing, and carcass cutting areas, respectively, than in the office area. The risk of COVID-19 infection was 2.1 times higher among employees of subcontractors than among employees of contractors. The COVID-19 risk levels were 5.3- and 3.0-fold higher in foreign workers than in native Korean workers in the PSPFs and MSPFs, respectively. CONCLUSION: As the COVID-19 pandemic continues, a detailed policy for infectious disease prevention and control intervention is needed, without interrupting economic activities. Thus, we propose an ideal intervention plan to prevent COVID-19 through disinfection and preemptive testing and to block its transmission through effective contact management during outbreaks at SPFs.

COVID-19 outbreak and risk factors for infection in a taekwondo gym in the Republic of Korea.

OBJECTIVES: Relatively few studies have assessed risk factors for coronavirus disease 2019 (COVID-19) in public facilities used by children and adolescents. This study presents an analysis of a COVID-19 outbreak that occurred in a taekwondo gym in Korea, predominantly among children and adolescents, with the aim of providing insights on managing COVID-19 outbreaks in similar facilities. METHODS: All 108 taekwondo gym students and staff received COVID-19 tests. A survey and closed-circuit television analyses were used to identify risk factors. A univariate analysis was conducted, followed by multivariate logistic regression analysis with backward elimination for variables with a significance level <0.10 in the univariate analysis. RESULTS: COVID-19 was confirmed in 30 of 108 subjects at the taekwondo gym (attack rate, 27.8%). The outbreak started in an adult class student. This student transmitted the virus to the staff, who consequently transmitted the virus to adolescent students. In the univariate analysis, the relative risk for younger age (≤9 years) was 2.14 (95% confidence interval [CI], 1.01-4.54; p=0.054), and that for food consumption inside the gym was 2.12 (95% CI, 1.04-4.30; p=0.048). In the multivariate logistic regression analysis, the odds ratio for younger age was 2.96 (95% CI, 1.07-8.20; p=0.036), and that for food consumption inside the gym was 3.00 (95% CI, 1.10-8.17; p=0.032). CONCLUSION: Food consumption inside the facility and young age were significant risk factors for COVID-19 transmission in this taekwondo gym. Food consumption should be prohibited in sports facilities, and infection prevention education for young students is also required.

Risk of Water and Food-Borne Communicable Diseases in Travelers Entering Korea.

OBJECTIVES: It was supposed to analyze status and affecting factors in water and food-borne communicable disease by screening entrants with diarrhea symptom at the point of entry in Korea. METHODS: Symptomatic travelers with water and food-borne communicable diseases who entered Korea were diagnosed by a health declaration and detection of causative agents in water and food using laboratory tests. Among those entered in 2017, the affecting factors in the incidence of communicable diseases among those who had diarrhea at the entry into Korea, were analyzed, with frequency and chi-square test. RESULTS: The number of travel entrants with gastrointestinal communicable diseases increased by 40.19% from 2013 to 2017. The percentage of causative agents of water and food-borne communicable diseases was the highest at 69.2% from July to September. The rate of detection of causative agents of communicable disease pathogens in travelers from Southeast Asia entering Korea was 70.2%, which was higher than people arriving from East Asia and Central Asia (57.5%; p < 0.001). CONCLUSION: The positive ratio of causative agents of water and food-borne communicable diseases was high among travelers that had entered Korea from July to September, with a high number among entrants from Southeast Asia. Based on the positive detection of causative agents, the entry period and countries visited were statistically significant affecting factors (p < 0.001).

Public health crisis preparedness and response in Korea.

Since the 2006 Pandemic Influenza Preparedness and Response Plan according to the World Health Organization's recommendation, the Republic of Korea has prepared and periodically evaluated the plan to respond to various public health crises including pandemic influenza. Korea has stockpiled 13,000,000 doses of antiviral drugs covering 26% of the Korean population and runs 519 isolated beds in 16 medical institutions. The division of public health crisis response in Korea Centers for Disease Control and Prevention are in charge of responding to public health crises caused by emerging infectious diseases including severe acute respiratory syndrome, avian influenza human infection, and pandemic influenza. Its job description includes preparing for emerging infectious diseases, securing medical resources during a crisis, activating the emergency response during the crisis, and fortification of capabilities of public health personnel. It could evolve into a comprehensive national agency to deal with public health crisis based on the experience of previous national emerging infectious diseases.

Allergic rhinitis in laboratory animal workers and its risk factors.

BACKGROUND: The workers in an animal laboratory are exposed to laboratory animal allergens (LAAs). OBJECTIVES: To evaluate the difference of sensitization to LAAs and the symptoms according to the exposure levels and to investigate the risk factors for sensitization to LAAs. METHODS: The subjects were divided into 3 groups according to the presence or absence of exposure: 74 subjects were in the direct exposure group, 33 subjects were in the indirect exposure group, and 30 subjects were in the control group. Each group answered the questionnaire and underwent skin prick tests that included 10 common allergens and 10 LAAs. The levels of total IgE and specific IgE to mouse and rat urine allergen were measured by enzyme-linked immunosorbent assay in 2 exposure groups. Allergic symptoms, skin sensitization, and serum IgE level were compared between the study groups. RESULTS: Twenty-five (34%) of the 74 subjects in the direct exposure group experienced allergic symptoms since their exposure to laboratory animals. The subjects in the direct and indirect exposure groups had more sensitization to LAAs than did the control subjects. The direct exposure group had more positive results for total IgE than did the indirect exposure group. The subjects in the direct exposure group with atopy had more severe allergic symptoms than the subjects in the indirect exposure group with atopy. Atopy and total IgE level were risk factors for the sensitization to LAAs for the direct exposure group (odds ratios, 7.47 and 7.33, respectively). CONCLUSIONS: Indirect exposure may be as risky for sensitization to LAAs as direct exposure. More careful protection is needed for laboratory animal workers with atopy.