COVID-19 in South Korea.

A novel coronavirus (severe acute respiratory syndrome-CoV-2) that initially originated from Wuhan, China, in December 2019 has already caused a pandemic. While this novel coronavirus disease (COVID-19) frequently induces mild diseases, it has also generated severe diseases among certain populations, including older-aged individuals with underlying diseases, such as cardiovascular disease and diabetes. As of 31 March 2020, a total of 9786 confirmed cases with COVID-19 have been reported in South Korea. South Korea has the highest diagnostic rate for COVID-19, which has been the major contributor in overcoming this outbreak. We are trying to reduce the reproduction number of COVID-19 to less than one and eventually succeed in controlling this outbreak using methods such as contact tracing, quarantine, testing, isolation, social distancing and school closure. This report aimed to describe the current situation of COVID-19 in South Korea and our response to this outbreak.

The Implications of Using Digital Technologies in the Management of COVID-19: Comparative Study of Japan and South Korea.

BACKGROUND: Technology can assist in providing effective infectious disease management, but it can also become a source of social injustice and inequality. To control the rapidly increasing SARS-CoV-2 infections and promote effective vaccine administration, both South Korea and Japan have been using several technology-based systems and mobile apps. However, their different approaches to technology use have yielded contrasting social implications. OBJECTIVE: Through comparative studies of the use of digital technologies for pandemic management and its social implications in Japan and South Korea, this study aimed to discuss whether the active and optimal use of technology for pandemic management can occur without subverting or compromising important social values, such as privacy and equality. METHODS: This study compared the social implications of Japan's and South Korea's contrasting approaches to technology implementation for COVID-19 pandemic management in early 2022. RESULTS: Digital technologies have been actively and comprehensively used in South Korea, enabling effective COVID-19 management, but have raised serious concerns about privacy and social equality. In Japan, technologies have been more carefully implemented, thereby not causing similar social concerns, but their effectiveness in supporting COVID-19 regulations has been criticized. CONCLUSIONS: Potential social implications such as equality concerns, the balance between public interest and individual rights, and legal implications must be carefully assessed in conjunction with effective and optimal infectious disease control to achieve sustainable use of digital health technologies for infectious disease management in the future.

National Trends in Sadness, Suicidality, and COVID-19 Pandemic-Related Risk Factors Among South Korean Adolescents From 2005 to 2021.

Importance: Despite the COVID-19 pandemic's effect on daily life, limited research exists on the prevalence and risk factors of suicidality and sadness among South Korean adolescents. Objectives: To examine whether the observed sadness and suicidality in the early to middle periods of the COVID-19 pandemic differed from the expected level and to investigate changes in risk factors for sadness and suicidality. Design, Setting, and Participants: This nationwide serial cross-sectional survey study used data on 1 109 776 Korean adolescents aged 13 to 18 years from the Korea Youth Risk Behavior Web-based Survey from 2005 to 2021. Exposure: The COVID-19 pandemic. Main Outcomes and Measures: The pattern of changes in the percentage or proportion of sadness or suicidality, as well as the risk factors for sadness or suicidality. The transitional effect of the COVID-19 pandemic was assessed using weighted odds ratios (wORs) or weighted beta coefficients with 95% CIs. Results: Between 2005 and 2021, 1 109 776 adolescents (mean [SD] age, 15.0 [1.7] years; 51.5% male adolescents; and 51.7% in grades 7-9 and 48.3% in grades 10-12) were included in the Korea Youth Risk Behavior Web-based Survey. The slope of the long-term trends in sadness and suicidality decreased in the prepandemic period (sadness: from 37.8% [95% CI, 37.4%-38.2%] in 2005-2007 to 26.1% [95% CI, 25.9%-26.4%] in 2016-2019; suicidality: from 23.0% [95% CI, 22.7%-23.3%] in 2005-2007 to 12.3% [95% CI, 12.1%-12.5%] in 2016-2019), whereas the slope increased during the COVID-19 pandemic (sadness: from 25.0% [95% CI, 24.5%-25.6%] in 2020 to 26.6% [95% CI, 26.1%-27.1%] in 2021; trend difference in ß, 0.249 [95% CI, 0.236-0.262]; suicidality: from 10.7% [95% CI, 10.3%-11.1%] in 2020 to 12.5% [95% CI, 12.1%-12.9%] in 2021; trend difference in ß, 0.328 [95% CI, 0.312-0.344]). The trends presented a similar tendency in the subgroups according to sex, school grade, residential area, smoking status, and current alcohol use. Compared with the prepandemic period, the risk factors associated with sadness during the pandemic were younger age (wOR, 0.907; 95% CI, 0.881-0.933), female sex (wOR, 1.031; 95% CI, 1.001-1.062), urban residence (wOR, 1.120; 95% CI, 1.087-1.153), current smoking status (wOR, 1.134; 95% CI, 1.059-1.216), and current alcohol use (wOR, 1.051; 95% CI, 1.002-1.102). Female sex (wOR, 1.064; 95% CI, 1.021-1.109), urban residence (wOR, 1.117; 95% CI, 1.074-1.162), and low economic status (wOR, 1.286; 95% CI, 1.180-1.403) were the risk factors significantly associated with suicidality after the COVID-19 pandemic began. Conclusions and Relevance: In this nationwide serial cross-sectional survey study of South Korean adolescents, the slope of the prevalence of sadness and suicidality increased during the COVID-19 pandemic after a decrease prior to the pandemic. The findings suggest that public health measures are needed to recognize vulnerable groups with risk factors and to prevent an increase in sadness and suicidality among adolescents during the COVID-19 pandemic.

Physical distancing and emergency medical services utilization after self-harm in Korea during the early COVID-19 pandemic: A nationwide quantitative study.

BACKGROUND: People experienced various stress and psychological responses to the coronavirus disease 2019 (COVID-19) pandemic. This study aimed to examine the changes in emergency medical services (EMSs) utilization by self-harm patients in early pandemic and the impacts of physical distancing measures on the EMSs utilization by self-harm patients. METHODS: Data for all patients presenting to emergency departments (EDs) after self-harm injuries including self-poisoning were collected from the National ED Information System (NEDIS). Characteristics of patients in two study regions (urban versus rural) were compared. Weekly and annual ED visit rates after self-harm (VRSH) per 100,000 population were calculated. Mobile phone mobility index (MPMI) was calculated by dividing a region's aggregated mobile phone mobility by mid-year population. Joinpoint regression analysis was conducted to assess changes in 2020 over pre-pandemic years. Test for presence of joinpoint at the end of 2019 was performed. A cross-correlation function was used to estimate the maximal morphological similarity and lag time between changes in MPMI and VRSH. RESULTS: In 2020, in early phases of the pandemic, there was a moderate decline in self-harm-related ED visits to 30,797 from a continuously increasing trend seen in previous years. However, proportions of young people (50.1%) and females (62.3%) increased over previous years. VRSHs among women and young people aged 15-34 years showed higher levels in 2020 than in previous five years. There was a significant decrease in the proportion of patients transported directly from the scene. In addition, there was a polarization of mental state upon ED arrival from alert and unresponsive. The median correlation coefficient between MPMI values and VRSH values was 0.601 (interquartile range [IQR]: 0.539-0.619) in urban regions and 0.531 (IQR: 0.454-0.595) in rural regions, showing no statistically significant difference between the two. CONCLUSION: Physical distancing measures adopted to prevent the spread of transmittable diseases following the pandemic had the effect of decreasing ED visits due to self-harm. When the pandemic has ended, and daily life has been restored, it will be particularly important to pay attention to the increased numbers of self-harm patients expected to visit EDs compared to during the pandemic.

The association between depression and non-compliance with COVID-19 preventive behaviors in South Korean older adults stratified by sex.

OBJECTIVES: This study evaluated the association between depression and non-compliance with COVID-19 preventive behaviors among community-dwelling South Korean older adults. METHODS: We utilized the 2020 Korean Community Health Survey-a community-based nationwide survey. A score of 10 points or higher on the Patient Health Questionnaire-9 was defined as depression. Non-compliance with COVID-19 preventive behaviors was assessed on the following three behaviors: washing hands, wearing masks, and watching distance. We also included socio-demographic characteristics, health behaviors, and COVID-19-related characteristics as covariates. Multiple logistic regression analyses were performed, and all statistical analyses were stratified by sex. RESULTS: The 70,693 participants included 29,736 men and 40,957 women. Notably, 2.3% of men and 4.2% of women had depression. Non-compliance with washing hands was significantly higher in men than women (1.3% vs. 0.9%), whereas no significant differences were observed in wearing masks and watching distance. The adjusted logistic regression analysis showed that depression was positively associated with non-compliance with washing hands and watching distance in both sexes. The association between depression and non-compliance with wearing masks was significant only in women. CONCLUSIONS: There was an association between depression and non-compliance with COVID-19 preventive behaviors in South Korean older adults. This signifies that health providers need to reduce depression to improve compliance with preventive behaviors in older adults.

Behavioral predictors associated with HIV screening needs in gay Korean men during the COVID-19 pandemic.

During the pandemic, the capacity of medical resources focused on testing, diagnosing and treating COVID-19 has severely limited public access to health care. In particular, HIV screening, for which homosexual males in Korea received free and anonymous testing at public health centers, was completely halted. This study investigated behavioral predictors related to the HIV screening needs of Korean male homosexuals during the pandemic. Data were collected by conducting a web survey targeting members of the largest homosexual portal site in Korea with support from the National Research Foundation of Korea (n = 1,005). The key independent variables are COVID-19-related characteristics and sexual risk behavior. The moderating variable is health information search behavior, and the dependent variable is the need for HIV screening. For a statistical analysis, a hierarchical multiple logistic regression analysis was conducted while controlling for potential confounding variables. According to the results of this study, the need for HIV screening was 0.928 times lower for older people (p<0.05, 95% CI = 0.966-0.998). However, if the respondent had a primary partner, the need for HIV screening was 1.459 times higher (p<0.01, 95% CI = 1.071-1.989). In addition, the need for screening was 1.773 times higher for those who preferred anal intercourse (p<0.01, 95% CI = 1.261-2.494) and 2.034 times higher (p<0.01, 95% CI = 1.337-3.095) if there was a history of being diagnosed with an STD. Finally, health information-seeking behavior was marginally significant. This study revealed that male Korean homosexuals who were young, preferred anal sex with a primary partner, and who had a history of a sexually transmitted disease had a high need for HIV screening at public health centers. They are more likely to be susceptible to HIV infection because they are usually consistent with gay men, characterized by risky behavior. Therefore, an intervention strategy that provides health information using a communication campaign is needed.

Association between COVID-19 lockdown and sleep behaviors in Korean adolescents.

To find the effect of coronavirus disease 2019 (COVID-19)-related sleep behavior changes using school-based self-reported data from a nationally representative Korean adolescent population. We analyzed web-based self-reported data from the Korean Youth Risk Behavior Web-based Survey in 98,126 participants (51,651 in 2019 [before the COVID-19 pandemic]; 46,475 in 2020 [during COVID-19 pandemic] 12 through 18 years old were included in this study. Self-report questionnaires were used to assess socioeconomic status, health behaviors, psychological factors, and sleep patterns. During the COVID-19 pandemic, Korean adolescents had a later weekend bedtime (≥1:00 am: 68.2% vs 71.5%, P < .001) and late weekend wake time (≤7:00 am: 13.3% vs 10.7%, P < .001) compared to before COVID-19 pandemic. Average sleep duration (434.7 ± 102.6 vs 428.2 ± 100.4 minutes; P < .001) was significantly lower during the COVID-19 pandemic and weekend catch-up sleep >2 hours (42.1% vs 43.7%; P < .001), late chronotype (17.1% vs 22.9%, P < .001) were significantly higher during COVID-19 pandemic. After adjusting for multiple confounding variables, short sleep duration (≦5 hours, odds ratio [OR] 1.14; 95% confidence interval [CI] 1.10-1.19), 6 hours, OR 1.07; 95% CI 1.03-1.12), long weekend catch-up sleep (OR, 1.08; 95% CI, 1.06-1.11) and late chronotype (OR, 1.43; 95% CI, 1.38-1.47) were significantly associated with COVID-19 pandemic. The COVID-19 pandemic was associated with changes in sleep behavior among Korean adolescents, resulting in later bed and wake-up times, increased weekend catch-up sleep, and a shift of chronotype toward eveningness.

Trends in the Quality of Primary Care and Acute Care in Korea From 2008 to 2020: A Cross-sectional Study.

OBJECTIVES: Measuring the quality of care is paramount to inform policies for healthcare services. Nevertheless, little is known about the quality of primary care and acute care provided in Korea. This study investigated trends in the quality of primary care and acute care. METHODS: Case-fatality rates and avoidable hospitalization rates were used as performance indicators to assess the quality of primary care and acute care. Admission data for the period 2008 to 2020 were extracted from the National Health Insurance Claims Database. Case-fatality rates and avoidable hospitalization rates were standardized by age and sex to adjust for patients' characteristics over time, and significant changes in the rates were identified by joinpoint regression. RESULTS: The average annual percent change in age-/sex-standardized case-fatality rates for acute myocardial infarction was -2.3% (95% confidence interval, -4.6 to 0.0). For hemorrhagic and ischemic stroke, the age-/sex-standardized case-fatality rates were 21.8% and 5.9%, respectively in 2020; these rates decreased since 2008 (27.1 and 8.7%, respectively). The average annual percent change in age-/sex-standardized avoidable hospitalization rates ranged from -9.4% to -3.0%, with statistically significant changes between 2008 and 2020. In 2020, the avoidable hospitalization rates decreased considerably compared with the 2019 rate because of the coronavirus disease 2019 pandemic. CONCLUSIONS: The avoidable hospitalization rates and case-fatality rates decreased overall during the past decade, but they were relatively high compared with other countries. Strengthening primary care is an essential requirement to improve patient health outcomes in the rapidly aging Korean population.

Two Years of Experience and Methodology of Korean COVID-19 Living Clinical Practice Guideline Development.

BACKGROUND: In Korea, during the early phase of the coronavirus disease 2019 (COVID-19) pandemic, we responded to the uncertainty of treatments under various conditions, consistently playing catch up with the speed of evidence updates. Therefore, there was high demand for national-level evidence-based clinical practice guidelines for clinicians in a timely manner. We developed evidence-based and updated living recommendations for clinicians through a transparent development process and multidisciplinary expert collaboration. METHODS: The National Evidence-based Healthcare Collaborating Agency (NECA) and the Korean Academy of Medical Sciences (KAMS) collaborated to develop trustworthy Korean living guidelines. The NECA-supported methodological sections and 8 professional medical societies of the KAMS worked with clinical experts, and 31 clinicians were involved annually. We developed a total of 35 clinical questions, including medications, respiratory/critical care, pediatric care, emergency care, diagnostic tests, and radiological examinations. RESULTS: An evidence-based search for treatments began in March 2021 and monthly updates were performed. It was expanded to other areas, and the search interval was organized by a steering committee owing to priority changes. Evidence synthesis and recommendation review was performed by researchers, and living recommendations were updated within 3-4 months. CONCLUSION: We provided timely recommendations on living schemes and disseminated them to the public, policymakers and various stakeholders using webpages and social media. Although the output was successful, there were some limitations. The rigor of development issues, urgent timelines for public dissemination, education for new developers, and spread of several new COVID-19 variants have worked as barriers. Therefore, we must prepare systematic processes and funding for future pandemics.

COVID-19 vaccination-related myocarditis: a Korean nationwide study.

AIMS: A comprehensive nationwide study on the incidence and outcomes of COVID-19 vaccination-related myocarditis (VRM) is in need. METHODS AND RESULTS: Among 44 276 704 individuals with at least 1 dose of COVID-19 vaccination, the incidence and clinical courses of VRM cases confirmed by the Expert Adjudication Committee of the Korea Disease Control and Prevention Agency were analyzed. COVID-19 VRM was confirmed in 480 cases (1.08 cases per 100 000 persons). Vaccination-related myocarditis incidence was significantly higher in men than in women (1.35 vs. 0.82 per 100 000 persons, P < 0.001) and in mRNA vaccines than in other vaccines (1.46 vs. 0.14 per 100 000 persons, P < 0.001). Vaccination-related myocarditis incidence was highest in males between the ages of 12 and 17 years (5.29 cases per 100 000 persons) and lowest in females over 70 years (0.16 cases per 100 000 persons). Severe VRM was identified in 95 cases (19.8% of total VRM, 0.22 per 100 000 vaccinated persons), 85 intensive care unit admission (17.7%), 36 fulminant myocarditis (7.5%), 21 extracorporeal membrane oxygenation therapy (4.4%), 21 deaths (4.4%), and 1 heart transplantation (0.2%). Eight out of 21 deaths were sudden cardiac death (SCD) attributable to VRM proved by an autopsy, and all cases of SCD attributable to VRM were aged under 45 years and received mRNA vaccines. CONCLUSION: Although COVID-19 VRM was rare and showed relatively favorable clinical courses, severe VRM was found in 19.8% of all VRM cases. Moreover, SCD should be closely monitored as a potentially fatal complication of COVID-19 vaccination.

The impact of the COVID-19 pandemic on chlamydia infection in South Korea: a comparison between the pre-pandemic and during-pandemic periods.

Background: Prior to COVID-19 pandemic, a yearly upward trajectory in the number of chlamydia infection cases was observed in South Korea. However, in response to the COVID-19 pandemic, Korea implemented several public health and social measures, which were shown to have an impact on the epidemiology of other infectious diseases. This study aimed to estimate the impact of the COVID-19 pandemic on the incidence and number of reported chlamydia infections in South Korea. Methods: Using the monthly number of reported chlamydia infection data between 2017 and 2022, we compared the trends in the reported numbers, and the incidence rates (IR) of chlamydia infection stratified by demographic characteristics (sex, age group, and region) in the pre- and during COVID-19 pandemic period (January 2017-December 2019 and January 2020-December 2022). Results: We observed an irregular downward trajectory in the number of chlamydia infection in the during-pandemic period. A 30% decrease in the total number of chlamydia infection was estimated in the during-pandemic compared to the pre-pandemic period, with the decrease greater among males (35%) than females (25%). In addition, there was a decrease in the cumulative incidence rate of the during COVID-19 pandemic period (IR: 0.43; 95% CI: 0.42-0.44) compared to the pre-pandemic period (IR: 0.60; 95% CI: 0.59-0.61). Conclusions: We identified decrease in the number of chlamydia infection during COVID-19 pandemic which is likely due to underdiagnosis and underreporting for the infection. Therefore, strengthening surveillance for sexually transmitted infections including chlamydia is warranted for an effective and timely response in case of an unexpected rebound in the number of the infections.

Evaluating factors influencing customers' intention to eat Korean cuisine "Samgyeopsal" in the Philippines: A structural equation model forest classifier approach.

Samgyeopsal has become a widely popular cuisine in the Philippines since 2014. The rise of Samgyeopsal is evident worldwide as it is available in countries such as the United States, Northern, and Southern Asia. This study aimed to explore the intention to eat Samgyeopsal during the COVID-19 pandemic utilizing structural equation modeling and random forest classifier. With a total of 1014 responses collected online, the result showed that utilitarian and hedonic motivation, Korean influence, and attitude led to very high actual behavior in east Samgyeopsal in the Philippines. Moreover, subjective norm, perceived behavioral control, and intention led to significant results influencing intention to actual behavior. Lastly, the COVID-19 safety protocol showed the least significant result. This study is the first study that evaluated the intention of consumers to eat Samgyeopsal in the Philippines during the COVID-19 pandemic. The results of this study would be beneficial to Korean BBQ restaurateurs and the further development of their marketing strategies even in other countries. Finally, the model construct of this study can be extended and applied in evaluating the consumers' eating intention toward other varieties of food or cuisines worldwide.

Association between Consumption of Dietary Supplements and Chronic Kidney Disease Prevalence: Results of the Korean Nationwide Population-Based Survey.

Despite the enormous global market of dietary supplements, the impact of dietary supplements on kidney disease is still unclear. Based on the National Health and Nutrition Examination Survey from 2015 to 2017, this study evaluated the association between dietary supplement and chronic kidney disease (CKD) in 13,271 Korean adults. Among the dietary supplements, vitamin and mineral intake was the highest at 61.41%, followed by omega-3 fatty acids at 11.85%, and ginseng at 7.99%. The prevalence of CKD was significantly higher in those who consumed amino acids and proteins, ginseng and red ginseng, and herbal medicine (plant extract)-berries than in those who did not. Conversely, patients who consumed probiotic supplements had a significantly lower prevalence of CKD than those who did not. In the population without CKD risk factors or history of CKD, the prevalence of CKD was high in the group consuming ginseng and red ginseng. After adjusting for covariates, the herbal medicine (plant extract)-berry group showed an independent association with CKD incidence. In conclusion, it is suggested that dietary supplements may affect kidney function. Further large-scale cohort studies are required to elucidate the exact effects of each dietary supplement on CKD.

[Factors Influencing the COVID-19 Vaccination Intentions in Parents for Their Children Aged 5~11: Korea, April 2022].

PURPOSE: This study aimed to investigate COVID-19 vaccination intentions in Korean parents for their children aged 5 to 11 years and the factors influencing them. METHODS: A cross-sectional online survey of 363 parents of children aged 5 to 11 years was conducted in Korea in April 2022. Data were analyzed using independent t-test, χ²-test, Fisher's exact test, and hierarchical logistic regression analysis using SPSS/WIN 26.0 and MedCalc software version 20.113. RESULTS: Of 363 Korean parents with children aged 5 to 11, 42.4% intended to vaccinate their children. Significant factors influencing vaccination intention were the second or third birth order of children (OR = 3.45, 95% CI = 1.45~8.21), vaccine hesitancy-confidence (OR = 2.00, 95% CI = 1.51~2.65), vaccine hesitancy-collective responsibility (OR = 1.57, 95% CI: 1.10~2.25), and COVID-19 anxiety-avoidance (OR = 1.55, 95% CI = 1.13~2.11). CONCLUSION: Findings suggest that COVID-19 vaccine campaigns based on reliable information and evidence from health authorities are needed to increase COVID-19 vaccination. Well-designed health communications for the target population may help to increase parental vaccine acceptance.

Effectiveness of Heterologous COVID-19 Vaccine Booster in Korean Elderly Population, 2022.

We conducted a cohort study to assess vaccine effectiveness (VE) of coronavirus disease 2019 vaccine combinations on severe acute respiratory syndrome coronavirus 2 critical infection and death among elderly population in Korea. From January to August 2022, VE against death for 4 doses mRNA recipients was 96.1%, whereas 1-dose viral vector + 3-dose mRNA recipients had VE of 90.8%.

The association mental health of adolescents with economic impact during the COVID-19 pandemic: a 2020 Korean nationally representative survey.

BACKGROUND: COVID-19 has affected innumerable aspects of life, including education, economy, and religion. Economic problems and inequality are associated with poor mental health in adolescents. This study aimed to identify the relationship between economic damage to families due to COVID-19 and various mental health problems in Korean adolescents and to evaluate the risk factors of mental health. METHODS: In total, 54,948 Korean adolescent students from 398 middle and 395 high schools were surveyed between August and November 2020. Complex sample logistic regression was performed to calculate odds ratios (ORs) and 95% confidence intervals (CI) for depression and suicidal ideation, respectively. A generalized linear model analysis was used to examine the association between mental health (unhappiness, loneliness, and stress) and the economic impact of COVID-19. Analyses were adjusted for age, gender, school grade, perceived academic achievement, perceived family economic status, and economic support. RESULTS: The ORs of depression (OR = 1.77, 95% CI:1.57-2.00), suicidal ideation (OR = 2.14, 95% CI:1.84-2.50), unhappiness (OR = 1.51 95% CI 1.42-1.60) and lonely (OR = 1.38 95% CI 1.27-1.49) for the low level of perceived family economic status was higher compared to middle level. Adolescents who experienced economic deterioration in their households as COVID-19 showed a higher risk of depression (OR = 1.42, 95% CI:1.35-1.49), suicide ideation (OR = 1.36, 95% CI:1.28-1.44), unhappiness (OR = 2.23 95% CI 2.19-2.27), lonely (OR = 1.20 95% CI 1.17-1.22), and stress (OR = 1.14 95% CI 1.12-1.16) than those who did not. CONCLUSIONS: The findings revealed an association between the decline in household economic status due to COVID-19 and mental health problems, such as stress, loneliness, suicidal ideation, depression, and unhappiness.

Changes in food and nutrient intakes in Korean adults before and during the COVID-19 pandemic: data from the 2011-2020 Korea National Health and Nutrition Examination Survey.

OBJECTIVES: This study was to examine the changes in dietary habits and food and nutrient intakes between before (2019) and during (2020) the coronavirus disease 2019 (COVID-19) pandemic from the Korea National Health and Nutrition Examination Survey (KNHANES). METHODS: A total of 54,995 participants aged ≥19 years who participated in the 2011-2020 KNHANES were included. The 10-year trend (2011-2020) and differences between 2019 and 2020 for dietary habits and food and nutrient intakes were estimated using SAS. RESULTS: In the past 10 years (2011-2020), the dietary habits (increase in skipping meals and eating out), food intake (increase in meats and decrease in fruits and vegetables), and nutrient intake (increase in fat and decrease in sodium) in adults have changed. When comparing between 2019 and 2020, there were 4.6%p decrease in the eating out more than once a day. On the other hand, there were no significant differences in the intakes of food, energy and most of nutrients between 2019 and 2020, except for the proportion of energy intake from fat (1.0%p increase) and carbohydrate (1.0%p decrease). CONCLUSIONS: Although a change in dietary habits from before to during the COVID-19 pandemic was observed, food and nutrient intakes have not deteriorated markedly and appear similar to the trends in the past 10 years. Throughout the COVID-19 pandemic, it is necessary to monitor the effects of changes in dietary habits on health as well as food and nutrient intakes.

Trends in health behaviors and mental health among Korean adolescents in Korea over 5 years, 2017-2021: focusing on the comparisons before and during the COVID-19 pandemic.

Objectives: We investigated recent trends in health behaviors and mental health conditions among Korean adolescents from 2017 to 2021 and compared the changes before and during the coronavirus disease 2019 (COVID-19) pandemic. Methods: Data analysis was conducted on 289,415 adolescents participating in the Korea Youth Risk Behavior Web-Based Survey, an annual cross-sectional study from 2017 to 2021. All analysis was conducted using sex stratification, and the annual percentage change (APC) was calculated. Results: Alcohol consumption and smoking decreased in the first year of the COVID-19 pandemic compared with before, except for girls from the low-income level. The prevalence of inadequate physical activity for both boys and girls increased in 2020 compared with the pre-COVID-19 period and decreased again by 2021. The prevalence of obesity in both sexes increased regardless of the period (boys, APC = 8.2%, 95% confidence intervals (CI), 6.4-10.1; girls, APC = 3.3%, 95% CI, 1.8-4.8). The prevalence of stress, depression, and suicidal ideation, plans, and attempts for both sexes decreased in 2020 compared to the pre-COVID-19 period. By 2021, this prevalence had returned to a level similar to before the pandemic. No significant APC changes were observed in the prevalence of mental health. Conclusions: These findings demonstrate the trends and APCs in health behaviors and mental health conditions among Korean adolescents over the last 5 years. We must pay attention to the heterogeneous and multifaceted features of the COVID-19 pandemic.

Self-reported adverse events after 2 doses of COVID-19 vaccine in Korea.

OBJECTIVES: In Korea, a national coronavirus disease 2019 (COVID-19) vaccination program was implemented, including 4 vaccines against COVID-19. A text messaging-based survey, in addition to a passive adverse event reporting system, was launched to quickly report unusual symptoms post-vaccination. This study compared the frequency of adverse events after COVID-19 vaccination based on the vaccine type and the type of 2-dose regimen (homologous or heterologous). METHODS: Self-reported adverse events were collected through a text-message survey for 7 days after each vaccination. This study included 50,950 vaccine recipients who responded to the survey at least once. Informed consent to receive surveys via text was obtained from the vaccine recipients on the date of first vaccination. RESULTS: The recipients of mRNA vaccines reported local and systemic reactions 1.6 times to 2.8 times more frequently after dose 2 than after dose 1 (p<0.001), whereas ChAdOx1-S recipients reported significantly fewer local and systemic reactions after dose 2 than after dose 1 (p<0.001). Local and systemic reactions were approximately 2 times and 4 times more frequent for heterologous vaccination than for BNT162b2/BNT162b2 and ChAdOx1-S/ChAdOx1-S regimens, respectively. Young individuals, female, and those receiving heterologous vaccine regimens including ChAdOx1-S/BNT162b2 vaccines reported more adverse events than older participants, male, and those with homologous vaccine regimens. CONCLUSIONS: Although a heterologous regimen, youth, and female sex were associated with a higher risk of adverse reactions after COVID-19 vaccination, no critical issues were noted. Active consideration of heterologous schedules based on the evidence of efficacy and safety appears desirable.