Factors Related to the Transmission of COVID-19 within Households from Pediatric Initial Cases

Abstract

Objectives: This study aims to identify pediatric COVID-19 transmission the general and epidemiological characteristics within households and determine odds ratios (OR) of transmission based on these characteristics. Methods: This study analyzed all laboratory-confirmed (PCR +) initial pediatric COVID-19 cases aged 0 to 18 years reported in Daegu, Republic of Korea, between February 18, 2020, and December 31, 2021 (n = 1,348). Household transmission was defined as households where at least one secondary case occurs within 1 to 14 days after the pediatric initial case. The study excluded cases that were known as the index case in the household but were identified as a secondary case through epidemiological investigation. Additionally, if the source of infection was unknown, they were excluded, provided at least one family member confirmed positive on the laboratory-contact test, including cases with incomplete epidemiological investigation. Results: 469 cases (34.8%) experienced household transmission. Male, symptomatic and cases with unknown source of infection had higher OR of transmitting COVID-19 to the household compared to the opposite scenarios (Male: OR, 1.36; 95% CI, 1.07-1.74; Symptomatic: OR, 1.93; 95% CI, 1.36-2.73; unknown source of infection: OR, 2.26; 95% CI, 1.59-3.21). Moreover, the age group of 4-6 years had the highest OR of transmitting COVID-19 to household contacts compared to the age group of 13-18 years (OR, 3.59; 95% CI, 2.55-5.05), and the age groups of 7-12 years (OR, 2.62; 95% CI, 1.94-3.53) and 0-3 years (OR, 2.25; 95% CI, 1.22-4.15) also showed higher ORs. However, the OR for the Ct value was 0.98 (95% CI, 0.96-0.99). Conclusions: This study suggests that male, symptomatic and cases with unknown sources in pediatric COVID-19 patients are more likely to transmit COVID-19 within households. Younger pediatric patients have higher OR for COVID-19 households transmission than older ones. However, the high Ct value indicated a lower likelihood of transmission.