Epidemiological Characteristics and Transmission Patterns of COVID-19 Cases Among Children and Adolescents Aged 0–18 Years in South Korea

Abstract

Background: In South Korea, the epidemiological characteristics of children and adolescents infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) have not been reported to date. The purpose of this study was to identify major epidemiological characteristics and transmission patterns of coronavirus disease 2019 (COVID-19) in children and adolescents. Methods: This study was conducted through a system integrated in an epidemiological investigation by the Korea Disease Control and Prevention Agency from January 20, 2020, to June 5, 2021. We analyzed the epidemiological characteristics of 14,967 children and adolescents with COVID-19 according to the age groups and transmission age patterns of 3721 infector-infectee pairs in South Korea. Results: Among the total confirmed COVID-19 cases, 14,967 patients were aged 0-18 years. The most affected age group among children and adolescents were those aged 16-18 years (3589, 24.0%). For all age groups, the infection route through friends and family members (31.9%) was the highest. For the contact age pattern analysis, infection from infectors aged 30-49 years to infectees aged 0-12 years showed a statistically significant relation (p <0.001) compared to that in other age groups. On the other hand, among the infectees aged 13-15 years and 16-18 years were significantly related with adolescents aged 10-19 years (p <0.05). Conclusion: These results suggest that adolescents aged 13-18 years were more infected with COVID-19 than those aged 0-12 years. Furthermore, they are particularly more likely to be infected by friends and family members. Besides, in patients aged 13-18 years, transmission of SARS-CoV-2 was more common from adolescents to adolescents than from adults to adolescents. This research will provide scientific evidence for school policies and vaccine strategies for COVID-19 prevention in children and adolescents.

Air pollution might affect the clinical course of COVID-19 in pediatric patients

“…As the immune system undergoes changes in children and adolescents ( Bartlett et al, 1998 ), two age groups were considered: ≤ 12 years and 13–17 years. Moreover, the previous epidemiological studies have shown that individuals aged 13–17 years are far more likely to be infected with SARS-CoV-2 and experience symptomatic infection than ≤ 12 years ( Jang et al, 2022 , Ryan et al, 2022 ). Moreover, in the present study, these two age groups had a similar sex distribution and did not differ in frequencies of comorbidities.…”

COVID-19 Vaccine Effectiveness against Omicron Variant among Underage Subjects: The Veneto Region’s Experience

“…During the Omicron period, the estimated effectiveness of a primary cycle significantly decreased in time, resulting in an overall effectiveness equal to 35% (34-37) among children and 19% (16)(17)(18)(19)(20)(21) among adolescents. Third doses, available just for adolescents during the Omicron period, provided an overall VE of 38% (36-40).…”

“…In the Omicron scenario, the overall effectiveness afforded by a primary cycle with BNT162b2 among children was 35% (34)(35)(36)(37) and it ranged from 72% (69-74) in the first week from vaccination to 23% (20)(21)(22)(23)(24)(25)(26) after more than 70 days from vaccination. The primary cycle with the same vaccine among adolescents provided an overall VE of 17% (15)(16)(17)(18)(19)(20) with an initial value of 81% (76-85), which decreases until 8% (5)(6)(7)(8)(9)(10)(11). The overall protection afforded by a primary cycle with mRNA-1273 among adolescents was 30% (26)(27)(28)(29)(30)(31)(32)(33), ranging from 88% (81-92) in the first week to 20% (15)(16)(17)(18)(19)(20)(21)(22)(23)(24) after more than 10 weeks.…”

“…Such a thesis may be supported by evidence of a viral load in children like the one registered among adults [11] and by studies, suggesting that school reopening might have been associated with an increase in the epidemic curve [12]. However, evidence on the role of children and adolescents in boosting the epidemic provides mixed results [13][14][15][16].…”

Investigation of a SARS-CoV-2 outbreak in a Texas summer camp resulting from a single introduction

“…Even when infected, children usually develop milder disease (17) and emit fewer virus particles than adults (18). Outbreaks among schools report low secondary attack rates (4,19) with child-tochild transmission, which is significantly lower than adult-to-adult and adult-to-child transmission (19)(20)(21)(22). However, several studies have noted an important distinction between transmission among young children (age 6-12) and adolescents (23,24) with reports of larger and more frequent outbreaks among secondary schools (25).…”