Characteristics, contacts, and relative risk of SARS-CoV-2 infection among children during school closures

Abstract

Background: Characteristics of children with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in Taiwanese households is nascent. We sought to characterize SARS-CoV-2 infection, and estimate the relative risk of infection among children within households during school closures in Taipei and New Taipei City.

Methods: We reviewed consecutive children below 18 years presenting to our emergency department from May 18, 2021 to July 12, 2021 who underwent real-time reverse-transcription polymerase chain reaction (rRT-PCR) for SARS-CoV-2 from respiratory swabs. Demographics, symptoms, and contacts were captured from medical records. Household contact was defined as an individual with confirmed COVID-19 living in the same residence as the child.

Results: Among 56 children with SARS-CoV-2, twenty-five (45%) were male with mean age of 7.9 years. Symptoms were nonspecific, with 29% having fever, 32% having cough, and 48% were asymptomatic. The median cycle threshold (Ct) value of SARS-CoV-2 rRT-PCR was 25 (range 11-38). All 56 children reported 94 contacts with a COVID-19 patient, of which 99% were household contacts. The relative risk of infection was 8.5 (95% CI 5.0-14.7) for children whose parent(s) were COVID-19 patients, and 7.3 (95% CI 4.9-11.0) for children whose household grandparent(s) were patients, as compared to children without respective contacts. Children without COVID-19 contacts were all tested negative.

Conclusions: During school closures in Taipei and New Taipei City, children with SARS-CoV-2 infection in our cohort had one or more COVID-19 contacts, mostly within their households. While diagnosing pediatric COVID-19 is challenging as children were often asymptomatic, those without contacts were likely uninfected.

Keywords: COVID-19; Children; Household; SARS-CoV-2; School closure; Taiwan.

Figure 1

A diagram showing the study flow. Abbreviations: SARS-CoV-2 denotes severe acute respiratory syndrome coronavirus-2; rRT-PCR denotes real-time reverse-transcription polymerase chain reaction. There were no children who were both symptomatic and international travelers.

Figure 2

Interpersonal and temporal relationships of children with household and non-household COVID-19 contacts. (A) The proportion of contacts among positive and negative cases were presented as donut charts. All 56 positive cases reported 94 contacts: 93 household (dark red) and 1 non-household (light red) contacts; while 88 out of 299 negative cases reported 106 contacts: 79 household (dark blue) and 27 non-household (light blue) contacts. (B) A breakdown of all 200 COVID-19 contacts by interpersonal relationship to positive and negative cases presented as a horizontal bar chart with a similar household/non-household legend to (A). As children may report more than 1 COVID-19 contact, the amount of contacts was greater than the amount of children. (C) The distribution of positive and negative cases (red or blue in color) who had household or non-household contacts (dark or light in shade) presented as a timeline by symptom onset date. Even though schools were closed in Taipei and New Taipei City on May 18, 2021, the earliest symptom onset was on May 14. Three-quarters of positive cases started to have symptoms 1 week after school closure (May 25, 2021 onwards). For asymptomatic positive cases, onset date was the date of specimen collection.