We analyzed reports for 59,073 contacts of 5,706 coronavirus disease (COVID-19) index patients reported in South Korea during January 20-March 27, 2020. Of 10,592 household contacts, 11.8% had ...COVID-19. Of 48,481 nonhousehold contacts, 1.9% had COVID-19. Use of personal protective measures and social distancing reduces the likelihood of transmission.
We describe the epidemiology of a coronavirus disease (COVID-19) outbreak in a call center in South Korea. We obtained information on demographic characteristics by using standardized epidemiologic ...investigation forms. We performed descriptive analyses and reported the results as frequencies and proportions for categoric variables. Of 1,143 persons who were tested for COVID-19, a total of 97 (8.5%, 95% CI 7.0%-10.3%) had confirmed cases. Of these, 94 were working in an 11th-floor call center with 216 employees, translating to an attack rate of 43.5% (95% CI 36.9%-50.4%). The household secondary attack rate among symptomatic case-patients was 16.2% (95% CI 11.6%- 22.0%). Of the 97 persons with confirmed COVID-19, only 4 (1.9%) remained asymptomatic within 14 days of quarantine, and none of their household contacts acquired secondary infections. Extensive contact tracing, testing all contacts, and early quarantine blocked further transmission and might be effective for containing rapid outbreaks in crowded work settings.
•Comparative effectiveness analyses of different COVID-19 vaccines were performed.•Analyses were adjusted for public health and virological data from 41 countries.•Messenger RNA and adenovirus ...vaccines had significantly fewer cases and deaths over 6 months.•Inactivated virus vaccines had significantly more cases and deaths over the same period.
To compare messenger RNA (mRNA)–based and adenovirus-vectored vaccines (ADVVs) with inactivated virus vaccines (IVVs) using real-world aggregate data.
We performed longitudinal analyses of publicly accessible epidemiological, clinical, virological, vaccine-related, and other public health data from 41 eligible countries during the first half of 2021. The relationships between vaccination coverage and clinical outcomes were analyzed using repeated measures correlation analyses and mixed-effects modeling to adjust for potential mediating and confounding factors.
Countries that used mRNA and/or ADVV (n = 31) vs IVV, among other vaccine types (n = 10), had different distributions of age (42.4 vs 33.9 years, respectively; P-value = 0.0006), gross domestic product per capita ($ 38,606 vs $ 20,422, respectively; P <0.0001), and population sizes (8,655,541 vs 5,139,162, respectively; P-value = 0.36). After adjustment for country differences, the stringency of nonpharmaceutical interventions, and dominant SARS-CoV-2 variant types, populations that received mRNA and/or ADVV had significantly lower rates of cases and deaths over time (P <0.001 for each analysis). Populations vaccinated with IVV, among others, had significantly higher rates of cases and deaths over time (P <0.05 for each analysis).
The real-world effectiveness of IVV may be inferior to mRNA and/or ADVV, and prospective comparative studies are needed to critically evaluate the role of IVV in the context of contemporary SARS-CoV-2 variants.
We used national statistics from 1983-2015 to evaluate trends in mortality caused by infectious diseases in South Korea. Age-standardized mortality from infectious disease decreased from 43.5/100,000 ...population in 1983 to 16.5/100,000 in 1996, and then increased to 44.6/100,000 in 2015. Tuberculosis was the most common cause of death in 1983 and respiratory tract infections in 2015. We observed a significant decline in infant deaths caused by infectious diseases, but mortality in persons age >65 years increased from 135 deaths/100,000 population in 1996 to 307/100,000 in 2015. The relative inequality indices for respiratory tract infections, sepsis, and tuberculosis tended to increase over time. Although substantial progress has been achieved in terms of infant mortality, death rates from infectious disease has not decreased overall. Elderly populations with lower education levels and subgroups susceptible to respiratory infections and sepsis should be the focus of preventive policies.
ObjectiveTransmissibility of COVID-19 by children in the household is not clear. Herein, we describe children’s role in household transmission of COVID-19.Design and settingAll paediatric COVID-19 ...index cases and their household members reported from 20 January to 6 April 2020 in South Korea were reviewed. The secondary attack rate (SAR) from child index case to household secondary case was calculated. Epidemiological and clinical findings of child index case-household secondary case pair was assessed.ResultsA total of 107 paediatric COVID-19 index cases and 248 of their household members were identified. One pair of paediatric index-secondary household case was identified, giving a household SAR of 0.5% (95% CI 0.0% to 2.6%). The index case was self-quarantined at home after international travel, stayed in her room, but shared a meal table with the secondary case.ConclusionThe SAR from children to household members was low in the setting of social distancing, underscoring the importance of rigorous contact tracing and early isolation in limiting transmission within households.
Background Kawasaki disease (KD) is a systemic vasculitis of unknown etiology that primarily affects children under 5 years of age. Some researchers suggested a potential triggering effect of air ...pollution on KD, but the findings are inconsistent and limited by small sample size. We investigated the association between ambient air pollution and KD among the population of South Korea younger than 5 years using the National Health Insurance claim data between 2007 and 2019. Methods and Results We obtained the data regarding particulate matter ≤10 or 2.5 µm in diameter, nitrogen dioxide, sulfur dioxide, carbon monoxide, and ozone from 235 regulatory monitoring stations. Using a time-stratified case-crossover design, we performed conditional logistic regression to estimate odds ratios (OR) of KD according to interquartile range increases in each air pollutant concentration on the day of fever onset after adjusting for temperature and relative humidity. We identified 51 486 children treated for KD during the study period. An interquartile range increase (14.67 μg/m
) of particulate matter ≤2.5 µm was positively associated with KD at lag 1 (OR, 1.016; 95% CI, 1.004-1.029). An interquartile range increase (2.79 ppb) of sulfur dioxide concentration was associated with KD at all lag days (OR, 1.018; 95% CI, 1.002-1.034 at lag 0; OR, 1.022; 95% CI, 1.005-1.038 at lag 1; OR, 1.017; 95% CI, 1.001-1.033 at lag 2). Results were qualitatively similar in the second scenario of different fever onset, 2-pollutant model and sensitivity analyses. Conclusions In a KD-focused national cohort of children, exposure to particulate matter ≤2.5 µm and sulfur dioxide was positively associated with the risk of KD. This finding supports the triggering role of ambient air pollution in the development of KD.
The global impact of COVID-19 on children emphasises the need for effective vaccination. While most cases are mild, those with underlying conditions face severe risks. Public health agencies promote ...various paediatric vaccination approaches. Japan universally recommends vaccination, while Korea prioritises high-risk children. Despite similar healthcare systems, Japan’s coverage rates (19%–72%) surpass Korea’s (2%–55%). Korea’s child death rates are higher, indicating increased risk. Both lack methods to address individual risks, hindering prevention. This study advocates universal vaccination to mitigate future pandemics’ impact on children systematically.
•From 2001 to 2018, the average annual percent change (net drift) of HBsAg positivity was −5.9% (95% confidence interval (CI): −6.9%, −4.8%).•Proportion of women with anti-HBs positivity increased ...from 59.9% in 2001 to 75.8% in 2018 (P = 0.002).•We observed a concurrent decrease in HBsAg seropositivity and an increase in anti-HBs seropositivity among Korean women of childbearing age.
We estimated the impact of universal hepatitis B immunization using 18-year data of women who are of childbearing age in South Korea.
We used hepatitis B surface antigen (HBsAg) and antibody (anti-HBs) data of 145,993 women aged 20–49 years during 2001–2018 at the Gangnam CHA Medical Center. Annual prevalences of HBsAg and anti-HBs positivity were calculated and tested for linear trend. We conducted age-period-cohort (APC) analysis to obtain period and cohort effect.
Overall proportion of HBsAg positivity was 3.5% (n = 5050) and anti-HBs positivity was 75.3% (n = 109,907) during the study period. HBsAg positivity percentage decreased from 5.1% in 2001 to 2.5% in 2018 (P < 0.001) while anti-HBs positivity increased from 59.9% to 75.8% (P = 0.002). Average annual percent change of HBsAg positivity was −5.9% (95% confidence interval (CI): −6.9%, −4.8%). The period and cohort RR curve identified a consistent decrease in HBsAg positivity over time and across generations.
We observed a concurrent decrease in HBsAg and an increase in anti-HBs seropositivity among Korean women of childbearing age, implicating success in preventing vertical transmission.
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