Epidemiology and Health

COVID-19: Original Article

The bounds of meta-analytics and an alternative method: Ramalingam Shanmugam, Mohammad Tabatabai, Derek Wilus, Karan P. Singh; Epidemiol Health. 2024;46:e2024016. Published online January 7, 2024; DOI: https://doi.org/10.4178/epih.e2024016

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Abstract Summary PDF Supplementary Material: Abstract
OBJECTIVES
Meta-analysis is a statistical appraisal of the data analytic implications of published articles (Y), estimating parameters including the odds ratio and relative risk. This information is helpful for evaluating the significance of the findings. The Higgins I2 index is often used to measure heterogeneity among studies. The objectives of this article are to amend the Higgins I2 index score in a novel and innovative way and to make it more useful in practice.
METHODS
Heterogeneity among study populations can be affected by many sources, including the sample size and study design. They influence the Cochran Q score and, thus, the Higgins I2 score. In this regard, the I2 score is not an absolute indicator of heterogeneity. Q changes by bound as Y increases unboundedly. An innovative methodology is devised to show the conditional and unconditional probability structures.
RESULTS
Various properties are derived, including showing that a zero correlation between Q and Y does not necessarily mean that they are independent. A new alternative statistic, S2, is derived and applied to mild cognitive impairment and coronavirus disease 2019 vaccination for meta-analysis.
CONCLUSIONS
A hidden shortcoming of the Higgins I2 index is overcome in this article by amending the Higgins I2 score. The usefulness of the proposed methodology is illustrated using 2 examples. The findings have potential health policy implications.; Summary

Key Message
An approach to overcome the hidden shortcomings of Higgens I2 in meta-analysis. The approach has potential health policy implications.

COVID-19: Original Article

Forecasting the effects of vaccination on the COVID-19 pandemic in Malaysia using SEIRV compartmental models: Mei Cheng Lim, Sarbhan Singh, Chee Herng Lai, Balvinder Singh Gill, Mohd Kamarulariffin Kamarudin, Ahmed Syahmi Syafiq Md Zamri, Cia Vei Tan, Asrul Anuar Zulkifli, Mohamad Nadzmi Md Nadzri, Nur'ain Mohd Ghazali, Sumarni Mohd Ghazali, Nuur Hafizah Md Iderus, Nur Ar Rabiah Binti Ahmad, Jeyanthi Suppiah, Kok Keng Tee, Tahir Aris, Lonny Chen Rong Qi Ahmad; Epidemiol Health. 2023;45:e2023093. Published online October 17, 2023; DOI: https://doi.org/10.4178/epih.e2023093

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Abstract Summary PDF Supplementary Material: Abstract
OBJECTIVES
This study aimed to develop susceptible-exposed-infectious-recovered-vaccinated (SEIRV) models to examine the effects of vaccination on coronavirus disease 2019 (COVID-19) case trends in Malaysia during Phase 3 of the National COVID-19 Immunization Program amidst the Delta outbreak.
METHODS
SEIRV models were developed and validated using COVID-19 case and vaccination data from the Ministry of Health, Malaysia, from June 21, 2021 to July 21, 2021 to generate forecasts of COVID-19 cases from July 22, 2021 to December 31, 2021. Three scenarios were examined to measure the effects of vaccination on COVID-19 case trends. Scenarios 1 and 2 represented the trends taking into account the earliest and latest possible times of achieving full vaccination for 80% of the adult population by October 31, 2021 and December 31, 2021, respectively. Scenario 3 described a scenario without vaccination for comparison.
RESULTS
In scenario 1, forecasted cases peaked on August 28, 2021, which was close to the peak of observed cases on August 26, 2021. The observed peak was 20.27% higher than in scenario 1 and 10.37% lower than in scenario 2. The cumulative observed cases from July 22, 2021 to December 31, 2021 were 13.29% higher than in scenario 1 and 55.19% lower than in scenario 2. The daily COVID-19 case trends closely mirrored the forecast of COVID-19 cases in scenario 1 (best-case scenario).
CONCLUSIONS
Our study demonstrated that COVID-19 vaccination reduced COVID-19 case trends during the Delta outbreak. The compartmental models developed assisted in the management and control of the COVID-19 pandemic in Malaysia.; Summary

Key Message
The effectiveness of the Coronavirus disease 2019 (COVID-19) vaccination against the highly transmissible Delta variant remained uncertain during the initial phase of the Delta outbreak in Malaysia. The innovative use of compartmental models provided scientific evidence of the potential impact of COVID-19 vaccination in reducing COVID-19 case trends based on local epidemiological data and offered forecasts of COVID-19 case trends based on varying vaccination rates which assisted resource planning and enhanced healthcare system preparedness. This evidence played a crucial role in bolstering public confidence in vaccination efforts and assisted in the control and management of the pandemic.

COVID-19: Cohort Profile

Cohort profile: investigating SARS-CoV-2 infection and the health and psychosocial impact of the COVID-19 pandemic in the Canadian CHILD Cohort: Rilwan Azeez, Larisa Lotoski, Aimée Dubeau, Natalie Rodriguez, Myrtha E. Reyna, Tyler Freitas, Stephanie Goguen, Maria Medeleanu, Geoffrey L. Winsor, Fiona S. L. Brinkman, Emily E. Cameron, Leslie Roos, Elinor Simons, Theo J. Moraes, Piush J. Mandhane, Stuart E. Turvey, Shelly Bolotin, Kim Wright, Deborah McNeil, David M. Patrick, Jared Bullard, Marc-André Langlois, Corey R. Arnold, Yannick Galipeau, Martin Pelchat, Natasha Doucas, Padmaja Subbarao, Meghan B. Azad; Epidemiol Health. 2023;45:e2023091. Published online October 13, 2023; DOI: https://doi.org/10.4178/epih.e2023091

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Abstract Summary PDF Supplementary Material: Abstract
The coronavirus disease 2019 (COVID-19) pandemic has affected all Canadian families, with some impacted differently than others. Our study aims to: (1) determine the prevalence and transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among Canadian families, (2) identify predictors of infection susceptibility and severity of SARS-CoV-2, and (3) identify health and psychosocial impacts of the COVID-19 pandemic. This study builds upon the CHILD Cohort Study, an ongoing multi-ethnic general population prospective cohort consisting of 3,454 Canadian families with children born in Vancouver, Edmonton, Manitoba, and Toronto between 2009 and 2012. During the pandemic, CHILD households were invited to participate in the CHILD COVID-19 Add-On Study involving: (1) brief biweekly surveys about COVID-19 symptoms and testing; (2) quarterly questionnaires assessing COVID-19 exposure and testing, vaccination status, physical and mental health, and pandemic-driven life changes; and (3) in-home biological sampling kits to collect blood and stool. In total, 1,462 households (5,378 participants) consented to the CHILD COVID-19 Add-On Study: 2,803 children (mean±standard deviation [SD], 9.0±2.7 years; range, 0-17 years) and 2,576 adults (mean±SD, 43.0±6.5 years; range, 18-85 years). We will leverage the wealth of pre-pandemic CHILD data to identify risk and resilience factors for susceptibility and severity to the direct and indirect pandemic effects. Our short-term findings will inform key stakeholders and knowledge users to shape current and future pandemic responses. Additionally, this study provides a unique resource to study the long-term impacts of the pandemic as the CHILD Cohort Study continues.; Summary

Key Message
· This study of 1,462 Canadian families (5,378 individuals) leverages a decade of extensive pre-pandemic CHILD Cohort Study data to identify risk and resilience factors for susceptibility to the direct and indirect effects of the COVID-19 pandemic. · Our short-term findings will inform key stakeholders and knowledge users to shape current and future pandemic responses. · This study provides a unique resource to study the long-term impacts of the pandemic as the CHILD Cohort Study continues.

COVID-19: Original Article

Risk of lymphadenopathy from SARS-CoV-2 vaccination in Korea: a self-controlled case series analysis: Mi-Sook Kim, Bongyoung Kim, Jeong Pil Choi, Nam-Kyong Choi, Jung Yeon Heo, Jun Yong Choi, Joongyub Lee, Sang Il Kim; Epidemiol Health. 2023;45:e2023090. Published online October 13, 2023; DOI: https://doi.org/10.4178/epih.e2023090

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Abstract Summary PDF Supplementary Material: Abstract
OBJECTIVES
To assess the risk of lymphadenopathy following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination.
METHODS
A self-controlled case series design was used to determine whether the risk of lymphadenopathy was higher in the 1-day to 42-day risk interval after coronavirus disease 2019 (COVID-19) vaccination compared to the control period. In addition, subgroup analyses were conducted according to baseline characteristics, time since vaccination, and sensitivity analyses adjusted for the length of the risk interval.
RESULTS
The risk of developing lymphadenopathy in the risk interval (1-42 days) after COVID-19 vaccination compared to the control period was significantly increased, with a relative incidence (RI) of 1.17 (95% confidence interval [CI], 1.17 to 1.18) when the first, second, and third doses were combined. The RI was greater on the day of vaccination (1.47; 95% CI, 1.44 to 1.50). In subgroup analyses by baseline characteristics, a significantly increased risk or trend toward increased risk was observed in most subgroups except for those aged 70 years and older, with a significant increase in risk in younger individuals, those with a Charlson’s comorbidity index <5, and those who received mRNA vaccines (mRNA-1273>BNT162b2). Within the 1-day to 42-day post-dose risk period, the relative risk was highest during the 1-day to 7-day post-dose period (1.59; 95% CI, 1.57 to 1.60) compared to the control period, and then the risk declined. In the sensitivity analysis, we found that the longer the risk window, the smaller the RI.
CONCLUSIONS
SARS-CoV-2 vaccination is associated with a statistically significant increase in the risk of lymphadenopathy, and this risk was observed only with mRNA vaccines.; Summary

Korean summary
질병관리청의 코로나19 예방접종자료와 국민건강보험공단 자료를 이용하여 수행한 본 자기대조환자군 연구에서 코로나19 백신접종은 42일 내 림프절병증 발생위험을 1.17배 (95% 신뢰구간, 1.17-1.18) 증가시키는 것으로 나타났다. 이러한 위험의 증가는 mRNA 백신에 국한하여 관찰되었으며 연령이 낮을수록, 여성일수록 상대위험도가 높은 것으로 나타났다.

Key Message
This self-controlled case series study, using the Korea Disease Control and Prevention Agency COVID-19 vaccination database and the National Health Insurance Service database, showed an increased risk of developing lymphadenopathy following vaccination (RR 1.17; 95% CI, 1.17 to 1.18). The elevated risk of lymphadenopathy is specifically associated with mRNA platform vaccines, not viral vector vaccines, and is more pronounced in younger individuals and females.

COVID-19: Original Article

Effective vaccination strategies to control COVID-19 in Korea: a modeling study: Youngsuk Ko, Kyong Ran Peck, Yae-Jean Kim, Dong-Hyun Kim, Eunok Jung; Epidemiol Health. 2023;45:e2023084. Published online September 7, 2023; DOI: https://doi.org/10.4178/epih.e2023084

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Abstract Summary PDF Supplementary Material: Abstract
OBJECTIVES
In Korea, as immunity levels of the coronavirus disease 2019 (COVID-19) in the population acquired through previous infections and vaccinations have decreased, booster vaccinations have emerged as a necessary measure to control new outbreaks. The objective of this study was to identify the most suitable vaccination strategy for controlling the surge in COVID-19 cases.
METHODS
A mathematical model was developed to concurrently evaluate the immunity levels induced by vaccines and infections. This model was then employed to investigate the potential for future resurgence and the possibility of control through the use of vaccines and antivirals.
RESULTS
As of May 11, 2023, if the current epidemic trend persists without further vaccination efforts, a peak in resurgence is anticipated to occur around mid-October of the same year. Under the most favorable circumstances, the peak number of severely hospitalized patients could be reduced by 43% (n=480) compared to the scenario without vaccine intervention (n=849). Depending on outbreak trends and vaccination strategies, the best timing for vaccination in terms of minimizing this peak varies from May 2023 to August 2023.
CONCLUSIONS
Our findings suggest that if the epidemic persist, the best timing for administering vaccinations would need to be earlier than currently outlined in the Korean plan. It is imperative to continue monitoring outbreak trends, as this is key to determining the best vaccination timing in order to manage potential future surges.; Summary

Korean summary
본 연구는 자연감염 혹은 백신으로 획득된 면역의 저하를 고려한 수리모델을 사용하여 COVID-19에 대한 백신 접종 전략 분석 결과를 보인다. 시뮬레이션 결과는 추가 백신 접종이 없을 경우 재유행의 정점이 800명을 넘을 것임을 나타내며, 적절한 시기에 백신을 접종하면 최대 재원 위중증환자수를 약 40%까지 줄일 수 있음을 보인다. 본 연구는 확진자 추세의 지속적인 모니터링이 백신 접종의 적정 시기를 결정하고 미래 COVID-19의 재유행을 효과적으로 관리하는 데 필요하다는 점을 강조한다.

Key Message
Our study analyzes strategies for COVID-19 through vaccination, using a mathematical model considering waning immunity from past infections and vaccinations. Results indicate that a resurgence peak would reach more than 800 without further vaccination, and suggest vaccination in proper timing can reduce the peak size of administered severe patients by up to approximately 40%. The study emphasizes the importance of ongoing monitoring of outbreak trends to manage vaccination timing and future COVID-19 surges effectively.

COVID-19: Original Article

Body mass index and prevalence of metabolic syndrome among Korean adults before and after the COVID-19 outbreak: a retrospective longitudinal study: Joo-Eun Jeong, Hoon-Ki Park, Hwan-Sik Hwang, Kye-Yeung Park, Myoung-Hye Lee, Seon-Hi Shin, Nayeon Choi; Epidemiol Health. 2023;45:e2023081. Published online August 29, 2023; DOI: https://doi.org/10.4178/epih.e2023081

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Abstract Summary PDF Supplementary Material: Abstract
OBJECTIVES
Studies evaluating weight changes during the coronavirus disease 2019 (COVID-19) pandemic have yielded inconsistent results, and most of those studies were based on self-reported anthropometric measures. We investigated changes in body mass index (BMI), professionally measured waist circumference (WC), and metabolic syndrome components from before to during the pandemic in a sample of the adult population in Korea.
METHODS
This retrospective study included 1,118 male and female (age≥18 years) who underwent health checkups at a university medical center between January 1, 2016 and March 31, 2022. Changes in BMI, lifestyles, and metabolic syndrome components during the pandemic were analyzed using the paired t-test, McNemar test, generalized estimating equations, and repeated-measures analysis of variance.
RESULTS
Changes in body weight, BMI, and body fat percentage during the pandemic were not clinically significant. However, statistically significant results were found for decreased physical activity (p<0.001) and WC (p<0.001), and exacerbation of all metabolic syndrome components (except serum triglyceride levels). Moreover, the metabolic syndrome prevalence increased significantly from 20.2% to 31.2% during the pandemic (p<0.001). The prevalence of abdominal obesity and high fasting blood glucose levels also significantly increased from 2019 to 2021.
CONCLUSIONS
Metabolic syndrome, its components, and fat distribution worsened significantly after the implementation of social distancing and lockdowns, despite no clinically significant changes in body weight and BMI. Further studies on the post- pandemic period should investigate the long-term impact of social lockdowns on BMI and the prevalence of metabolic syndrome.; Summary

Korean summary
본 연구에서는 한국인 성인들의 코로나 팬대믹으로 인한 사회적 거리 두기, 봉쇄 정책 전 후의 체질량지수, 생활습관, 그리고 대사증후군과 그 구성 요소들의 변화를 건강검진을 통해 측정한 객관적인 지표의 변화를 통해 알아보고자 하였다. 연구 결과, 사회적 거리 두기 및 봉쇄 전후의 체질량지수와 체중은 유의미한 변화가 없었으나, 신체 활동량은 유의미하게 감소하였고, 체지방률, 허리둘레가 늘어났다. 그리고 중성지방을 제외하고 다른 대사증후군의 구성 요소인 혈압, 고밀도지단백 콜레스테롤, 공복혈당 지표는 악화되었다. 하위 그룹 분석에서 매년 검진을 시행 받은 대상자들 및 고혈압, 당뇨병, 이상지질혈증 약을 복용하지 않는 대상자들의 코로나-19 전후 연도별 대사 지표의 변화를 분석한 결과, 복부비만 유병률과 공복 혈당의 증가 양상이 뚜렷하였다.

Key Message
Although there was no significant change in BMI and weight, the prevalence of metabolic syndrome, abdominal obesity, and fasting blood glucose level prominently worsened after the implementation of social distancing and lockdowns. Such findings may indicate deterioration of insulin resistance during the COVID-19 pandemic. This study provides valuable information for healthcare professionals, policymakers, and the general public towards mitigating the negative consequences of the pandemic on metabolic health, regardless of weight gain.

COVID-19: Original Article

Clinical symptom profile of hospitalized COVID-19 Brazilian patients according to SARS-CoV-2 variants: Natália Satchiko Hojo-Souza, Vander Luis de Souza Freitas, Daniel Ludovico Guidoni, Fernanda Sumika Hojo de Souza; Epidemiol Health. 2023;45:e2023079. Published online August 28, 2023; DOI: https://doi.org/10.4178/epih.e2023079

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Abstract Summary PDF

Abstract

OBJECTIVES
The aim of this study was to investigate the prevalence of the main symptoms in Brazilian coronavirus disease 2019 (COVID-19) patients hospitalized during 4 distinct waves, based on their infection with different severe acute respiratory disease coronavirus 2 (SARS-CoV-2) variants.

METHODS

This study included hospitalized patients who tested positive for SARS-CoV-2 during 15 weeks around the peak of each of 4 waves: W1, ancestral strain/B.1 lineage (May 31 to September 12, 2020); W2, Gamma/P.1 variant (January 31 to May 15, 2021); W3, Omicron variant (December 5, 2021 to March 19, 2022); and W4, BA.4/BA.5 subvariants (May 22 to September 3, 2022). Symptom data were extracted from the Brazilian Severe Acute Respiratory Syndrome Database. Relative risks were calculated, and an analysis of symptom networks was performed.

RESULTS

Patients who were hospitalized during the prevalence of the Gamma/P.1 variant demonstrated a higher risk, primarily for symptoms such as fatigue, abdominal pain, low oxygen saturation, and sore throat, than patients hospitalized during the first wave. Conversely, patients who were hospitalized during the predominance of the Omicron variant exhibited a lower relative risk, particularly for symptoms such as loss of smell, loss of taste, diarrhea, fever, respiratory distress, and dyspnea. Similar results were observed in COVID-19 patients who were hospitalized during the wave of the Omicron subvariants BA.4/BA.5. A symptom network analysis, conducted to explore co-occurrence patterns among different variants, revealed significant differential profiles across the 4 waves, with the most notable difference observed between the W2 and W4 networks.

CONCLUSIONS

Overall, the relative risks and patterns of symptom co-occurrence associated with different SARS-CoV-2 variants may reflect disease severity.

Summary

Key Message
The study highlights the varying prevalence and distinct symptom profiles among Brazilian COVID-19 patients hospitalized during different waves linked to specific SARS-CoV-2 variants. It suggests that the manifestation of symptoms differs significantly across variant-driven waves, signifying potential shifts in disease severity. Specifically, patients during the Gamma/P.1 variant wave showed higher risks for symptoms like fatigue, abdominal pain, and respiratory impairment, while those during the Omicron wave exhibited lower risks for certain symptoms like loss of smell and taste, indicating changing symptomatology and potentially evolving disease impact linked to different variants.

Citations

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Gastrointestinal symptoms in COVID-19 and disease severity: a Japanese registry-based retrospective cohort study
Yuta Matsubara, Hiroki Kiyohara, Yohei Mikami, Kosaku Nanki, Ho Namkoong, Shotaro Chubachi, Hiromu Tanaka, Shuhei Azekawa, Shinya Sugimoto, Yusuke Yoshimatsu, Tomohisa Sujino, Kaoru Takabayashi, Naoki Hosoe, Toshiro Sato, Makoto Ishii, Naoki Hasegawa, Yuk
Journal of Gastroenterology.2024; 59(3): 195. CrossRef
Prevalence and Factors Associated with Olfactory Dysfunction in Individuals with COVID-19 in Brazil: A Study of 20,669 Cases from 2020 to 2021
Carlos Dornels Freire de Souza, Amanda Júlia de Arruda Magalhães, Yasmin Vitória Silva Nobre, Carlos Alberto Souza, André Luis Oliveira do Nascimento, Luísa Robalinho de Faria, Márcio Bezerra-Santos, Anderson da Costa Armstrong, Jandir Mendonça Nicácio, O
Medical Principles and Practice.2024; : 1. CrossRef
Risks of Adverse Outcomes for Hospitalized COVID-19 Patients during the Four Waves in Brazil According to SARS-CoV-2 Variants, Age Group, and Vaccine Status
Natália Satchiko Hojo-Souza, Waasila Jassat, Daniel Ludovico Guidoni, Fernanda Sumika Hojo de Souza
Viruses.2023; 15(10): 1997. CrossRef

COVID-19: Original Article

Korea Seroprevalence Study of Monitoring of SARS-COV-2 Antibody Retention and Transmission (K-SEROSMART): findings from national representative sample: Jina Han, Hye Jin Baek, Eunbi Noh, Kyuhyun Yoon, Jung Ae Kim, Sukhyun Ryu, Kay O Lee, No Yai Park, Eunok Jung, Sangil Kim, Hyukmin Lee, Yoo-Sung Hwang, Jaehun Jung, Hun Jae Lee, Sung-il Cho, Sangcheol Oh, Migyeong Kim, Chang-Mo Oh, Byengchul Yu, Young-Seoub Hong, Keonyeop Kim, Sun Jae Jung, Mi Ah Han, Moo-Sik Lee, Jung-Jeung Lee, Young Hwangbo, Hyeon Woo Yim, Yu-Mi Kim, Joongyub Lee, Weon-Young Lee, Jae-Hyun Park, Sungsoo Oh, Heui Sug Jo, Hyeongsu Kim, Gilwon Kang, Hae-Sung Nam, Ju-Hyung Lee, Gyung-Jae Oh, Min-Ho Shin, Soyeon Ryu, Tae-Yoon Hwang, Soon-Woo Park, Sang Kyu Kim, Roma Seol, Ki-Soo Park, Su Young Kim, Jun-wook Kwon, Sung Soon Kim, Byoungguk Kim, June-Woo Lee, Eun Young Jang, Ah-Ra Kim, Jeonghyun Nam, The Korea Community Health Survey Group, Soon Young Lee, Dong-Hyun Kim; Epidemiol Health. 2023;45:e2023075. Published online August 17, 2023; DOI: https://doi.org/10.4178/epih.e2023075

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Abstract Summary PDF Supplementary Material

Abstract

OBJECTIVES
We estimated the population prevalence of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including unreported infections, through a Korea Seroprevalence Study of Monitoring of SARS-CoV-2 Antibody Retention and Transmission (K-SEROSMART) in 258 communities throughout Korea.

METHODS

In August 2022, a survey was conducted among 10,000 household members aged 5 years and older, in households selected through two stage probability random sampling. During face-to-face household interviews, participants self-reported their health status, COVID-19 diagnosis and vaccination history, and general characteristics. Subsequently, participants visited a community health center or medical clinic for blood sampling. Blood samples were analyzed for the presence of antibodies to spike proteins (anti-S) and antibodies to nucleocapsid proteins (anti-N) SARS-CoV-2 proteins using an electrochemiluminescence immunoassay. To estimate the population prevalence, the PROC SURVEYMEANS statistical procedure was employed, with weighting to reflect demographic data from July 2022.

RESULTS

In total, 9,945 individuals from 5,041 households were surveyed across 258 communities, representing all basic local governments in Korea. The overall population-adjusted prevalence rates of anti-S and anti-N were 97.6% and 57.1%, respectively. Since the Korea Disease Control and Prevention Agency has reported a cumulative incidence of confirmed cases of 37.8% through July 31, 2022, the proportion of unreported infections among all COVID-19 infection was suggested to be 33.9%.

CONCLUSIONS

The K-SEROSMART represents the first nationwide, community-based seroepidemiologic survey of COVID-19, confirming that most individuals possess antibodies to SARS-CoV-2 and that a significant number of unreported cases existed. Furthermore, this study lays the foundation for a surveillance system to continuously monitor transmission at the community level and the response to COVID-19.

Summary

Korean summary
인구집단을 기반으로 하여 대표성 있는 표본을 추출하여 COVID-19 항체유병률 조사를 전국적으로 수행함으로 지역사회 단위에서 지속적으로 모니터링할 수 있는 COVID-19 감시체계 구축의 기반을 마련하였다. 2022년 8월 우리나라 국민의 대부분이 COVID-19에 대한 항체를 보유하고 있었고 인구 3명 중 1명은 미확진 감염자로 추정되었다.

Key Message
The K-SEROSMART represents the first nationwide, community-based seroepidemiologic survey of COVID-19. In August 2022, most of the Korean people had antibodies to COVID-19, and one in three people was estimated to have an unreported infection. This study lays the foundation for a surveillance system to continuously monitor transmission at the community level and the response to COVID-19.

Citations

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Infection-mediated immune response in SARS-CoV-2 breakthrough infection and implications for next-generation COVID-19 vaccine development
Sho Miyamoto, Tadaki Suzuki
Vaccine.2024; 42(6): 1401. CrossRef

COVID-19: Original Article

Did the socioeconomic inequalities in avoidable and unavoidable mortality worsen during the first year of the COVID-19 pandemic in Korea?: Rora Oh, Myoung-Hee Kim, Juyeon Lee, Rangkyoung Ha, Jungwook Kim; Epidemiol Health. 2023;45:e2023072. Published online August 3, 2023; DOI: https://doi.org/10.4178/epih.e2023072

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Abstract Summary PDF Supplementary Material: Abstract
OBJECTIVES
This study examined changes in socioeconomic inequalities in mortality in Korea before and after the outbreak of coronavirus disease 2019 (COVID-19).
METHODS
From 2017 to 2020, age-standardized mortality rates were calculated for all-cause deaths, avoidable deaths (preventable deaths, treatable deaths), and unavoidable deaths using National Health Insurance claims data and Statistics Korea’s cause of death data. In addition, the slope index of inequality (SII) and the relative index of inequality (RII) by six income levels (Medical Aid beneficiary group and quintile of health insurance premiums) were computed to analyze the magnitude and change of mortality inequalities.
RESULTS
All-cause and avoidable mortality rates decreased steadily between 2017 and 2020, whereas unavoidable mortality remained relatively stable. In the case of mortality inequalities, the disparity in all-cause mortality between income classes was exacerbated in 2020 compared to 2019, with the SII increasing from 185.44 to 189.22 and the RII increasing from 3.99 to 4.29. In particular, the preventable and unavoidable mortality rates showed an apparent increase in inequality, as both the SII (preventable: 91.31 to 92.01, unavoidable: 69.99 to 75.38) and RII (preventable: 3.42 to 3.66, unavoidable: 5.02 to 5.89) increased.
CONCLUSIONS
In the first year of the COVID-19 pandemic, mortality inequality continued to increase, although there was no sign of exacerbation. It is necessary to continuously evaluate mortality inequalities, particularly for preventable and unavoidable deaths.; Summary

Korean summary
이 연구는 COVID-19 발생 전후 한국에서의 사망률 추이와 사망률 불평등 변화를 조사했다. 2017~2020년 사이에 총사망률과 회피가능사망률은 줄어들었지만, 사망률의 사회경제적 불평등은 더 커지는 경향을 보였다. 특히 예방가능사망과 회피불가능사망에서 불평등이 커져 지속적인 추적과 평가가 필요하다.

Key Message
This study examined the trends in mortality rates and changes in mortality inequality in Korea before and after the onset of COVID-19. Between 2017 and 2020, while the all-cause and avoidable mortality rates decreased, there was a growing trend of inequality in mortality rates based on income levels. Particularly, inequalities in preventable and unavoidable deaths have increased, emphasizing the need for ongoing evaluation.

COVID-19: Original Article

Unequal burdens of COVID-19 infection: a nationwide cohort study of COVID-19-related health inequalities in Korea: Jeangeun Jeon, Jieun Park, Min-Hyeok Choi, Hongjo Choi, Myoung-Hee Kim; Epidemiol Health. 2023;45:e2023068. Published online July 31, 2023; DOI: https://doi.org/10.4178/epih.e2023068

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Abstract Summary PDF Supplementary Material: Abstract
OBJECTIVES
While the Korean government’s response to the coronavirus disease 2019 (COVID-19) pandemic is considered effective given the relatively low mortality rate, issues of inequality have been insufficiently addressed. This study explored COVID-19-related health inequalities in Korea.
METHODS
Age standardization for various health inequality indices was derived using data from the Korean National Health Insurance Service, the Korea Disease Control and Prevention Agency, and the Microdata Integrated Service of Statistics Korea. The slope index of inequality (SII) and relative index of inequality (RII) were calculated for socioeconomic variables, while absolute difference (AD) and relative difference (RD) were used for gender and disability inequalities.
RESULTS
We observed a number of COVID-19-related health outcome inequalities. Gender inequality was particularly noticeable in infection rates, with the rate of women 1.16 times higher than that of men. In contrast, socioeconomic inequality was evident in vaccination rates, with a 4.5-fold (SII, -4.519; 95% confidence interval, -7.403 to -1.634) difference between the highest and lowest household income groups. Regarding clinical progression post-infection, consistent findings indicated higher risk for men (RD for hospitalization, 0.90; severe cases, 0.54; and fatality, 0.65), individuals with disabilities (RD for hospitalization, 2.27; severe cases, 2.29; and fatality, 2.37), and those from lower socioeconomic groups (SII for hospitalization, 1.778; severe cases, 0.089; and fatality, 0.451).
CONCLUSIONS
While the infection risk was nearly ubiquitous, not everyone faced the same level of risk post-infection. To prevent further health inequalities, it is crucial to develop a thoughtful policy acknowledging individual health conditions and resources.; Summary

Korean summary
2020년 10월-2022년 4월까지의 국내 코로나-19 확진자 데이터와 건강보험 빅데이터, 사망등록통계를 연계하여 건강결과의 불평등 지표를 산출한 결과, 감염율, 백신접종율, 입원율, 중증화율, 치명률에서 소득수준(건강보험료 소득분위 기준), 성별, 장애유무에 따른 건강결과의 불평등이 확인되었다. 감염율은 여성이 남성보다 높았고, 백신접종율은 장애인과 의료급여 수급권자의 비율이 낮게 나타났고, 코로나-19로 인한 입원율과 중증화율, 치명율에서는 남성, 의료급여 수급권자, 장애인의 취약성이 두드러졌다. 본 연구의 분석결과는 국내 방역정책이 기존의 사회불평등을 충분하게 고려하지 못했을 가능성이 크며, 미래 감염병 관리 시 이를 고려하여 불평등을 완화시킬 수 있는 방향의 정책적 전략이 필요하다는 점을 시사한다.

Key Message
This study sought to investigate COVID-19-related health inequalities in Korea by linking COVID-19 registry data to the KNHIS big data and the cause of death data for the period October 2020 - April 2022. COVID-19-related health outcome inequalities were observed in infection, vaccination, hospitalization, clinical progress, and fatality by household income, gender, and disability. The infection rate was higher in women, the vaccination proportion was lower in the disabled and medical-aid beneficiaries, and men, the disabled and medical-aid beneficiaries were vulnerable in clinical progression post-infection which implies that a policy necessarily should consider existing socioeconomic inequalities for future pandemics.

COVID-19: Original Article

Direct indicators of social distancing effectiveness in COVID-19 outbreak stages: a correlational analysis of case contacts and population mobility in Korea: Sojin Choi, Chanhee Kim, Kun-Hee Park, Jong-Hun Kim; Epidemiol Health. 2023;45:e2023065. Published online July 10, 2023; DOI: https://doi.org/10.4178/epih.e2023065

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Abstract Summary PDF Supplementary Material: Abstract
OBJECTIVES
The effectiveness of social distancing during the coronavirus disease 2019 (COVID-19) pandemic has been evaluated using the magnitude of changes in population mobility. This study aimed to investigate a direct indicator—namely, the number of close contacts per patient with confirmed COVID-19.
METHODS
From week 7, 2020 to week 43, 2021, population movement changes were calculated from the data of two Korean telecommunication companies and Google in accordance with social distancing stringency levels. Data on confirmed cases and their close contacts among residents of Gyeonggi Province, Korea were combined at each stage. Pearson correlation analysis was conducted to compare the movement data with the change in the number of contacts for each confirmed case calculated by stratification according to age group. The reference value of the population movement data was set using the value before mid-February 2020, considering each data’s characteristics.
RESULTS
In the age group of 18 or younger, the number of close contacts per confirmed case decreased or increased when the stringency level was strengthened or relaxed, respectively. In adults, the correlation was relatively low, with no correlation between the change in the number of close contacts per confirmed case and the change in population movement after the commencement of vaccination for adults.
CONCLUSIONS
The effectiveness of governmental social distancing policies against COVID-19 can be evaluated using the number of close contacts per confirmed case as a direct indicator, especially for each age group. Such an analysis can facilitate policy changes for specific groups.; Summary

Korean summary
1. 사회적 거리두기의 효과를 간접적인 자료인 이동통신사와 구글데이터를 이용하여 인구 이동성 변화의 크기를 평가하였고, 직접적인 자료인 역학조사서의 확진자 1인당 밀접 접촉자 수를 산출하여 비교 평가하였다. 2. 18세 이하 연령대는 사회적 거리두기의 강화 또는 완화 단계에 따라 확진자 1인당 밀접 접촉자 수가 민감하게 변동되었으나, 성인의 경우에는 덜 민감하게 변동되었다. 3. 역학조사서에 기반하여 시계열 자료로 재가공한 확진자 1인당 밀접 접촉자 수는 사회적 거리두기 정책의 효과를 평가하는 직접적인 평가 지표로 사용될 수 있기에 충분히 검토되어야 한다.

Key Message
1. The study assessed social distancing's effectiveness by analyzing population mobility changes through mobile operator and Google data. And it was also compared with the number of close contacts per confirmed COVID-19 case based on the epidemiological survey report. 2. Younger age groups were more influenced by the social distancing policy in close contacts per confirmed COVID-19 case than adults. 3. The study suggests using close contacts per confirmed COVID-19 case from the epidemiological survey report as a direct measure of social distancing policy effectiveness.

COVID-19: Original Article

Barriers to COVID-19 vaccine surveillance: the issue of under-reporting adverse events: Yunha Noh, Hwa Yeon Ko, Ju Hwan Kim, Dongwon Yoon, Young June Choe, Seung-Ah Choe, Jaehun Jung, Ju-Young Shin; Epidemiol Health. 2023;45:e2023054. Published online June 7, 2023; DOI: https://doi.org/10.4178/epih.e2023054

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Abstract Summary PDF Supplementary Material

Abstract

OBJECTIVES
This study investigated the reporting rates of adverse events following immunization (AEFIs) to the spontaneous reporting system (SRS) and its predictors among individuals with AEFIs after coronavirus disease 2019 (COVID-19) vaccination.

METHODS

A cross-sectional, web-based survey was conducted from December 2, 2021 to December 20, 2021, recruiting participants >14 days after completion of a primary COVID-19 vaccination series. Reporting rates were calculated by dividing the number of participants who reported AEFIs to the SRS by the total number of participants who experienced AEFIs. We estimated adjusted odds ratios (aORs) using multivariate logistic regression to determine factors associated with spontaneous AEFIs reporting.

RESULTS

Among 2,993 participants, 90.9% and 88.7% experienced AEFIs after the first and second vaccine doses, respectively (reporting rates, 11.6 and 12.7%). Furthermore, 3.3% and 4.2% suffered moderate to severe AEFIs, respectively (reporting rates, 50.5 and 50.0%). Spontaneous reporting was more prevalent in female (aOR, 1.54; 95% confidence interval [CI], 1.31 to 1.81); those with moderate to severe AEFIs (aOR, 5.47; 95% CI, 4.45 to 6.73), comorbidities (aOR, 1.31; 95% CI, 1.09 to 1.57), a history of severe allergic reactions (aOR, 2.02; 95% CI, 1.47 to 2.77); and those who had received mRNA-1273 (aOR, 1.25; 95% CI, 1.05 to 1.49) or ChAdOx1 (aOR, 1.62; 95% CI, 1.15 to 2.30) vaccines versus BNT162b2. Reporting was less likely in older individuals (aOR, 0.98; 95% CI, 0.98 to 0.99 per 1-year age increment).

CONCLUSIONS

Spontaneous reporting of AEFIs after COVID-19 vaccination was associated with younger age, female sex, moderate to severe AEFIs, comorbidities, history of allergic reactions, and vaccine type. AEFIs under-reporting should be considered when delivering information to the community and in public health decision-making.

Summary

Korean summary
본 연구는 국내 19-49세 성인을 대상으로, 코로나19 예방 백신 접종 후 이상반응 경험에 대한 자발적 보고율을 조사하고, 자발적 보고와 관련된 요인을 파악하고자 하였다. 2021년 12월 2일부터 20일까지 온라인 설문조사를 통하여 자료를 수집하였으며, 연구대상자는 코로나19 예방 백신의 기초접종을 완료한 후 2주 경과한 19-49세 성인으로, 전국 대표성을 확보하기 위해 성별, 연령, 지역별로 층화하여 모집하였다. 이상반응 자발적 보고율은 1차 접종과 2차 접종 후 각각 약 11.6%, 12.7%로 나타났으며, 중등도에서 중증의 이상반응에 대한 자발적 보고율은 약 50.5%, 50.0%로 나타났다. 이상반응 자발적 보고율 관련 영향요인으로는 젊은 연령층, 여성, 이상반응의 중증도, 동반질환, 알러지 반응 이력, 기초접종 백신 종류가 포함되었다.

Key Message
Spontaneous reporting rates of adverse events following immunization (AEFIs) against coronavirus disease 2019 (COVID-19) were low, at around 12 % of any AEFIs and 50 % of moderate-to-severe AEFIs. Younger age, female sex, severe AEFIs, comorbidities, history of allergic reactions, and the type of COVID-19 vaccine were associated with the AEFIs reporting.

Citations

Citations to this article as recorded by

The effect of covid vaccination on menstruation and attitude to the vaccine among Indian women – Results of a prospective survey
Anbukkani Subbian, Jeevithan Shanmugam, Uma Ram
Indian Journal of Obstetrics and Gynecology Research.2024; 11(1): 70. CrossRef

COVID-19: Brief Communication

Prevalence of SARS-CoV-2 infection among urban cleaning and solid waste management workers during transmission of the Omicron variant in Brazil: Paulo Ricardo Martins-Filho, Joyce Thayane da Conceição dos Santos, Márcia Santos Rezende, Fernanda Oliveira de Carvalho, Érica Santos dos Reis, Waneska de Souza Barboza, Taise Ferreira Cavalcante, Cliomar Alves dos Santos, Lucindo José Quintans-Júnior, Renata Grespan, Cristiane Bani Corrêa, Tatiana Rodrigues de Moura, Dulce Marta Schimieguel, Jullyana de Souza Siqueira Quintans, Adriano Antunes de Souza Araújo; Epidemiol Health. 2023;45:e2023025. Published online February 16, 2023; DOI: https://doi.org/10.4178/epih.e2023025

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Abstract Summary PDF: Abstract
This study estimated the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in urban cleaning and solid waste management workers during the transmission of the Omicron variant in one of the poorest regions of Brazil (the state of Sergipe). Nasopharyngeal swabs were collected from 494 workers, and the presence of SARS-CoV-2 RNA was tested by quantitative reverse-transcriptase polymerase chain reaction. Data on socio-demographic characteristics, comorbidities, vaccination status, mask use, and use of public transport to commute to the workplace were collected. The prevalence with a 95% confidence interval (CI) was calculated from the proportion of SARS-CoV-2 positive cases among the total number of individuals tested. The prevalence ratio (PR) with a 95% CI was the measure of association used to evaluate the relationship between SARS-CoV-2 infection and the exposure variables. The prevalence of SARS-CoV-2 infection was 22.5% (95% CI, 19.0 to 26.4). Individuals under the age of 40 had a higher prevalence of infection (PR, 1.53; 95% CI, 1.03 to 2.30) as well as those who did not believe in the protective effect of vaccines (PR, 1.78; 95% CI, 1.05 to 2.89). Our results indicate the need for better guidance on preventive measures against coronavirus disease 2019 among urban cleaning and solid waste management workers.; Summary

Key Message
Urban cleaning and waste management workers in Brazil faced a significant risk of SARSCoV-2 infection during the Omicron variant transmission, with higher rates observed among younger individuals and those skeptical about vaccine protection.

COVID-19: Original Article

Changes in mental health service utilization before and during the COVID-19 pandemic: a nationwide database analysis in Korea: Kyoung Hoon Kim, Sang Min Lee, Minha Hong, Kyu-Man Han, Jong-Woo Paik; Epidemiol Health. 2023;45:e2023022. Published online February 14, 2023; DOI: https://doi.org/10.4178/epih.e2023022

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Abstract Summary PDF Supplementary Material

Abstract

OBJECTIVES
The present study examined the impact of the coronavirus disease 2019 (COVID-19) pandemic on mental health service utilization through a comparative analysis of nationwide data regarding inpatient care users, outpatient visits, emergency department (ED) visits, and admissions via the ED before and during the pandemic.

METHODS

Data from approximately 350,000 Koreans diagnosed with mental illness were analyzed in terms of hospitalization, outpatient visits, and ED visits between January 2018 and June 2021. An interrupted time series analysis was conducted to determine the significance of changes in mental health service utilization indicators.

RESULTS

The number of hospital admissions per patient decreased by 1.2% at the start of the pandemic and 0.7% afterward. The length of hospital stay increased by 1.8% at the outbreak of the pandemic, and then decreased by 20.2%. Although the number of outpatients increased, the number of outpatient visits per patient decreased; the number of outpatient visits for schizophrenia (3.4%) and bipolar disorder (3.5%) significantly decreased immediately post-outbreak. The number of ED visits per patient decreased both immediately post-outbreak and afterward, and ED visits for schizophrenia (19.2%), bipolar disorder (22.3%), and depression (17.4%) decreased significantly immediately post-outbreak. Admissions via the ED did not show a significant change immediately post-outbreak.

CONCLUSIONS

Mental health service utilization increased during the pandemic, but medical service use decreased overall, with a particularly significant decrease in ED utilization. As the pandemic worsened, the decline in outpatient visits became more pronounced among those with severe mental illness.

Summary

Korean summary
이 연구는 COVID-19 전후 정신질환 의료서비스 이용 변화를 분석하였다. 팬데믹 기간 중에 정신질환 의료서비스는 전반적으로 감소하였고, 특히 중증 정신질환의 외래 방문이 감소하였다. 따라서, 정신질환자의 진료 연속성을 보장하기 위한 조치가 요구된다.

Key Message
This study examined the impact of the COVID-19 pandemic on mental health service utilization. The mental health service utilization decreased overall after the outbreak of COVID-19, especially outpatient visits for severe mental illness significantly decreased. Therefore, countermeasures are needed to maintain the continuity of care.

Citations

Citations to this article as recorded by

Adult Mental Health Presentations to Emergency Departments in Victoria, Australia between January 2018 and October 2020: Changes Associated with COVID-19 Pandemic Public Health Restrictions
Jackson Newberry-Dupé, Wanyu Chu, Simon Craig, Rohan Borschmann, Gerard O’Reilly, Paul Yates, Glenn Melvin, Kylie King, Harriet Hiscock
Psychiatric Quarterly.2024; 95(1): 33. CrossRef

COVID-19: Special Article

Changes in mental health of Korean adolescents before and during the COVID-19 pandemic: a special report using the Korea Youth Risk Behavior Survey: Bomi Park, Jihee Kim, Jieun Yang, Sunhye Choi, Kyungwon Oh; Epidemiol Health. 2023;45:e2023019. Published online February 14, 2023; DOI: https://doi.org/10.4178/epih.e2023019

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Abstract Summary PDF Supplementary Material

Abstract

OBJECTIVES
We aimed to study the effects of the coronavirus disease 2019 (COVID-19) pandemic on adolescents’ mental health in Korea.

METHODS

We used data from the Korea Youth Risk Behavior Survey 2018-2021 with 227,139 students aged 12-18 years. We estimated the differences in depressive symptoms, suicidal ideation, and stress perception before (2018-2019) and during (2020-2021) the pandemic, as well as before (2019), the first year (2020) of, and the second year (2021) of the pandemic. We also examined whether COVID-19 is statistically associated with mental health.

RESULTS

In both male and female adolescents, the prevalence of depressive symptoms, suicidal ideation, and stress perception was higher in the “not living with family,” “low household economic status,” and “self-rated unhealthy status” subgroups. The prevalence of depressive symptoms and stress perception was higher in middle school students. Adolescents were less likely to experience depressive symptoms (adjusted odds ratio [aOR], 0.86; 95% confidence interval [CI], 0.83 to 0.89), suicidal ideation (aOR, 0.80; 95% CI, 0.76 to 0.83), and stress perception (aOR, 0.76; 95% CI, 0.74 to 0.79) in 2020 than in 2019. However, there were more depressive symptoms (aOR, 1.06; 95% CI, 1.02 to 1.09), suicidal ideation (aOR, 1.15; 95% CI, 1.10 to 1.21), and stress perception (aOR, 1.19; 95% CI, 1.16 to 1.23) in 2021 than in 2020.

CONCLUSIONS

The COVID-19 pandemic had positive impacts on mental health of adolescents in its early stages but has had negative impacts as the pandemic continues. Attention should be paid to adolescents who are particularly vulnerable to the mental health effects of the pandemic.

Summary

Korean summary
The results from a nationally representative data showed that mental health in adolescents was improved in the first year of the COVID-19 pandemic compared to before the COVID-19 pandemic, but it was deteriorated in the second year of the pandemic compared to the first year.

Key Message
본 연구에서는 대규모 건강조사를 이용하여 코로나19가 장기화됨에 따른 영향을 평가하고자 하였다. 2018년-2021년 청소년건강행태조사에 참여한 만 12-18세 청소년 227,139 명을 대상으로 분석한 결과, 코로나19 유행 첫번째 해(2020년)에는 코로나19 유행 이전에 비해 정신건강이 개선되었으나, 코로나19 유행 두 번째 해(2021년)에는 코로나19 유행 첫 번째 해에 비해 청소년 정신건강이 나빠졌다. 또한 가족과 함께 거주하지 않는 경우, 가정 경제 수준이 낮은 경우, 본인이 건강하지 않다고 인지하는 경우에 더 취약하였다.

Citations

Citations to this article as recorded by

Excess mortality during the Coronavirus disease pandemic in Korea
Changwoo Han, Hoyeon Jang, Juhwan Oh
BMC Public Health.2023;[Epub] CrossRef
A Comparison of Changes in Health Behavior, Obesity, and Mental Health of Korean Adolescents Before and During the COVID-19 Pandemic: Online Cross-Sectional Study
Mi-Sun Lee, Hooyeon Lee
Psychiatry Investigation.2023; 20(11): 1086. CrossRef

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