J Korean Med Sci.  2022 Oct;37(42):e303. 10.3346/jkms.2022.37.e303.

SARS-CoV-2-Naïve Korean Children and Adolescents Hospitalized With COVID-19 in 2021

• Choi YY
• Choi SH
• Choi JH
• Kim DH
• Lee JK
• Eun BW
• Lee H
• Kim YK
• Ahn B
• Song SH
• Yun KW

• KMID: 2534756
• DOI: http://doi.org/10.3346/jkms.2022.37.e303

Abstract

Background
The risk of severe outcomes with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) delta variant remains low in children and adolescents, but less is known about its effect on the SARS-CoV-2-naïve population. This study evaluated clinical manifestations and risk factors for moderate-to-critical coronavirus disease 2019 (COVID-19) in mostly SARS-CoV-2-naïve children and adolescents in 2021.
Methods
This multicenter retrospective study included patients aged 0–18 years who were hospitalized with COVID-19 at 8 referring hospitals in South Korea during the predeltapredominant and delta-predominant periods in 2021. Each case was labeled as either hospitalization with medical needs or for isolation. Severity was categorized as mild, moderate, severe, or critical with regard to pneumonia presence and illness severity.
Results
Among 753 cases, most (99.5%) had no prior history of COVID-19 or vaccination against COVID-19. The proportions of hospitalization with medical needs (3.5% vs. 19.7%), moderate illness (0.9% vs. 4.0%), and severe/critical illness (0.8% vs. 5.3%) increased during delta predominance. The risk of moderate-to-critical COVID-19 among hospitalizations with medical needs was higher among patients aged 12–18 years (adjusted odds ratio [aOR], 4.1; 95% confidence interval [CI], 1.5–11.8) and with obesity (aOR, 6.9; 95% CI, 2.4–19.6) but not among patients infected during delta predominance. However, children with obesity experienced more severe COVID-19 during delta predominance (aOR, 6.1; 95% CI, 1.2–29.6).
Conclusion
Despite its similar severity among most SARS-CoV-2-naïve children and adolescents, the delta variant may affect COVID-19 severity in those with high-risk underlying medical conditions. Underlying conditions, particularly obesity, may cause severe COVID-19 in children and adolescents, warranting strong consideration for vaccinating high-risk children.

Keyword

Coronavirus Disease 2019; Severe Acute Respiratory Syndrome Coronavirus 2; SARS-CoV-2 Variants

Figure

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  Fig. 1 Epidemiologic curve and isolation policy of SARS-CoV-2 infection, South Korea, 2021. (A) Weekly distribution of SARS-CoV-2 variants in domestic cases. The delta variant became predominant at week 30 (arrow); (B) Weekly national new cases in children and adolescents aged 0–19 years and changes in national isolation policy.VOC = variants of concern, SARS-CoV-2 = severe acute respiratory syndrome coronavirus 2.

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  Fig. 2 Monthly distribution of hospitalizations with COVID-19 among children and adolescents aged 0–18 years before and after SARS-CoV-2 delta predominance in 2021 by medical needs and disease severity. (A) Hospitalizations with medical needs in the predelta-predominant period; (B) Hospitalizations with medical needs in the delta-predominant period; (C) Moderate-to-critical disease in the predelta-predominant period; (D) Moderate-to-critical disease in the delta-predominant period.COVID-19 = coronavirus disease 2019, SARS-CoV-2 = severe acute respiratory syndrome coronavirus 2.

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