Short Term Impact of Coronavirus Disease 2019 Vaccination in Children in Korea

Lee, Hyunju; Choi, Eunhwa; Park, Young-Joon; Choe, Young June

doi:10.3346/jkms.2022.37.e124

Cited by 4 publications

(6 citation statements)

References 14 publications

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“…In South Korea, the increase of SARS‐CoV‐2 cases during the first half of 2022 was largely driven by children and adolescents with limited vaccine coverage, suggesting a possible role of vaccine‐induced immunity in preventing SARS‐CoV‐2 reinfections. 10 Higher rates of reinfection among children (470 per 100 000, compared to 240–280 per 100 000 in adults) and unvaccinated persons (530–640 per 100 000, compared to 210‐400 per 100 000 in fully vaccinated persons) support such hypothesis. This higher vaccination coverage could lead to a lesser chance of reinfections in the community.…”

Section: Discussionmentioning

confidence: 99%

“…This finding may reflect the difference in risk of exposure between the population, such as young adults and healthcare professionals, with a persistently higher risk of exposure compared to the general population. In South Korea, the increase of SARS‐CoV‐2 cases during the first half of 2022 was largely driven by children and adolescents with limited vaccine coverage, suggesting a possible role of vaccine‐induced immunity in preventing SARS‐CoV‐2 reinfections 10 . Higher rates of reinfection among children (470 per 100 000, compared to 240–280 per 100 000 in adults) and unvaccinated persons (530–640 per 100 000, compared to 210‐400 per 100 000 in fully vaccinated persons) support such hypothesis.…”

Section: Discussionmentioning

confidence: 99%

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Reinfection with SARS‐CoV‐2 in general population, South Korea; nationwide retrospective cohort study

Jang

Choe

Yun

et al. 2022

Journal of Medical Virology

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To better understand the epidemiology of SARS‐CoV‐2 reinfections, we analyzed national data from South Korean who were followed longitudinally from January 2020 to April 2022. We conducted a nationwide retrospective cohort study to estimate possible SARS‐CoV‐2 reinfection rates in all residents in South Korea, with at least two episodes of laboratory‐confirmed SARS‐CoV‐2 infection by reverse‐transcriptase polymerase chain reaction or rapid antigen test (RAT) performed at least 45 or more days between both episodes, between January 2020 and April 2022. There were 16 130 855 laboratory‐confirmed SARS‐CoV‐2 cases in South Korea, with 55 841 (346.2 per 100 000; or 0.3% of all infections) cases of possible reinfections. The reinfection rate has increased from 6.0 cases per 100 000 during Pre‐Delta period to 128.0 cases per 100 000 and 355.1 cases per 100 000 during Delta and Omicron periods, respectively. Persons with one dose of vaccination had the highest reinfection rate of 642.2 per 100 000, followed by unvaccinated persons (536.2/100 000) and two‐dose vaccinated persons (406.3/100 000). Our finding suggests that the majority of possible reinfections occurred following the emergence of new variants.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Reinfection with SARS‐CoV‐2 in general population, South Korea; nationwide retrospective cohort study

Jang

Choe

Yun

et al. 2022

Journal of Medical Virology

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“…Increase in mortality of ages 5 to 19 during the year 2021 coincides with rapid increase in COVID-19 patients of that particular age group [ 53 ]. Although COVID-19 vaccination for adults started in February 2021, the vaccination for adolescents (12 to 17 years) was delayed until October 2021 in Korea [ 54 ].…”

Section: Discussionmentioning

confidence: 99%

“…Although COVID-19 vaccination for adults started in February 2021, the vaccination for adolescents (12 to 17 years) was delayed until October 2021 in Korea [ 54 ]. Until the adoption of vaccination, 12 to 17 years age group showed highest incidence since the second quarter of 2021 [ 53 ], and this may have resulted in higher excess mortality of that age group during year 2021. Age-specific mortality patterns of the younger age group in our study also showed an increase in COVID-19 mortality since July 2021 (Figure S 3 ).…”

Section: Discussionmentioning

confidence: 99%

Excess mortality during the Coronavirus disease pandemic in Korea

Han,

Jang,

2023

BMC Public Health

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Background Although the ongoing epidemics of Coronavirus disease 2019 (COVID-19) may have affected the mortality trend of the nation, the national level assessment of excess mortality (changes in overall mortality in the entire population) is still scarce in Korea. Therefore, this study evaluated the excess mortality during the COVID-19 pandemic in Korea using the certified mortality data. Methods Monthly mortality and population data from January 2013 to June 2022 was obtained from the National Health Insurance Service database and Statistics Korea. A quasi-Poisson interrupted time-series model adjusted for age structure, population, seasonality, and long-term trends was used to estimate the counterfactual projections (expected) of mortality during the COVID-19 pandemic (March 2020 to June 2022). The absolute difference (observed—expected) and ratio (observed / expected) of mortality were calculated. Stratified analysis based on pandemic years (years 2020, 2021, and 2022), sex, and age groups (aged 0–4, 5–19, 20–64, and ≥ 65 years) were conducted. Results An 8.7% increase in mortality was observed during the COVID-19 pandemic [absolute difference: 61,277 persons; ratio (95% confidence interval (CI)): 1.087 (1.066, 1.107)]. The gap between observed and estimated mortality became wider with continuation of the pandemic [ratio (95% CI), year 2020: 1.021 (1.003, 1.040); year 2021: 1.060 (1.039, 1.080), year 2022: 1.244 (1.219, 1.270)]. Although excess mortality across sex was similar, the adult [aged 20–64, ratio (95% CI): 1.059 (1.043, 1.076)] and elderly [aged 65-, ratio (95% CI): 1.098 (1.062, 1.135)] population showed increased excess mortality during the pandemic. Conclusions Despite Korea's successful quarantine policy response, the continued epidemic has led to an excess mortality. The estimated mortality exceeded the number of deaths from COVID-19 infection. Excess mortality should be monitored to estimate the overall impact of the pandemic on a nation.

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“… 14 COVID-19 vaccination started in adolescents since October 2021, reaching vaccine coverage of 67.8% for one dose and 46.3% for two doses, by the end of 2021. 15 COVID-19 vaccination in children aged 5–11 started since March 2022, with low coverage of 1% by August 2022. 16 …”

Section: Methodsmentioning

confidence: 99%

Change in Severity and Clinical Manifestation of MIS-C Over SARS-CoV-2 Variant Outbreaks in Korea

Choe

Choi

et al. 2023

J Korean Med Sci

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Background There is difference in the incidence of multi-system inflammatory syndrome in children (MIS-C) in patients with different variants of severe acute respiratory syndrome coronavirus 2, however, little is known about the epidemiology in Asian countries. We investigated and compared the epidemiology of the MIS-C during omicron-dominant period with that of previous periods in South Korea. Methods We obtained clinical, epidemiological and laboratory data on MIS-C cases from national MIS-C surveillance in South Korea. We defined pre-delta period as January 2020–May 2021; delta period as June 2021–December 2021; and omicron period as January 2022–April 2022. We describe the clinical characteristics and outcomes of MIS-C patients by period. Results A total of 91 cases were assessed to be MIS-C cases. Number of MIS-C cases have increased from six cases during pre-delta period to 66 cases during omicron period, while the incidence rate (the number of MIS-C cases per 100,000 cases of reported coronavirus disease 2019) has decreased from 38.5 cases per 100,000 (95% confidence interval [CI], 14.1–83.9) during pre-delta period to 1.6 cases per 100,000 (95% CI, 1.2–2.0) during omicron periods. During pre-delta period, 66.7% and 100% had hypotension and gastrointestinal involvement, respectively; while during omicron period, 12.1% and 6.1% had such clinical manifestations. Fifty percent of pre-delta MIS-C patients were taken intensive care unit (ICU) cares, while 10.6% of patients during omicron periods were in ICUs. Conclusion Omicron period were associated with less severe clinical manifestation compared to pre-delta and delta periods. Although incidence rate of MIS-C was lower for the omicron period than pre-delta and delta periods, number of patients reported with MIS-C may pose a substantial clinical burden.

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Short Term Impact of Coronavirus Disease 2019 Vaccination in Children in Korea

Cited by 4 publications

References 14 publications

Reinfection with SARS‐CoV‐2 in general population, South Korea; nationwide retrospective cohort study

Reinfection with SARS‐CoV‐2 in general population, South Korea; nationwide retrospective cohort study

Excess mortality during the Coronavirus disease pandemic in Korea

Change in Severity and Clinical Manifestation of MIS-C Over SARS-CoV-2 Variant Outbreaks in Korea

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