Factors Associated with Hospital and Intensive Care Admission in Paediatric SARS-CoV-2 Infection: A Prospective Nationwide Observational Cohort Study

Background: Coronavirus disease 2019 (COVID-19) is usually less severe in children compared to adults. This study describes detailed clinical characteristics, treatment and outcomes of children with laboratory-confirmed COVID-19 in a non-hospitalised and hospitalised setting and quantifies factors associated with admission to hospital and intensive care unit in children with SARS-CoV-2 infection on a nationwide level. Methods: Data were collected through the Swiss Paediatric Surveillance Unit from children < 18 years with laboratory-confirmed SARS-CoV-2 infection. All 33 paediatric hospitals in Switzerland reported non-hospitalised and hospitalised cases from March 1 to October 31, 2020 during both pandemic peaks. Findings: In total, 678 children were included. The median age was 12.2 (IQR 5.0 – 14.6) years, 316 (47%) were female and 106 (16%) had comorbidities. Overall, 126 (18.6%) children were hospitalised of whom 16 (12.7%) required ICU admission. Comorbidities were the only factor associated with hospital admission in a multivariable regression analysis (odds ratio 3.23, 95%CI 1.89 to 5.50; p-value <0.01). Hospitalised children more often presented with fever (96 [76.2%] vs 209 [38.1%], p-value<0.01) and rash (16 [12.8%] vs 6 [1.1%], p-value<0.01). Anosmia/dysgeusia was more prevalent in non-hospitalised children (73 [13.3%] vs 3 [2.4%], p-value<0.01). In the hospitalised children, oxygen treatment was required in 34 (27.0%), inotropes in nine (7.3%) and mechanical ventilation in eight (6.3%). Complications were reported in 28 (4.1%) children with cardiovascular complications being most frequent (11 [1.6%]). Three deaths were recorded. Interpretation: This study confirms that COVID-19 is mostly a mild disease in children. Fever, rash, and comorbidities are associated with higher admission rates. Continuous observation is necessary to further understand paediatric COVID-19, guide therapy and evaluate the necessity for vaccination in children. Funding: The study is supported by the Swiss Federal Office of Public Health and has received grants from the Swiss Society of Paediatrics and the Paediatric Infectious Disease Group of Switzerland. Declaration of Interest: None to declare. Ethical Approval: The study has received ethical approval by the Ethikkommission Nordwest- und Zentralschweiz (EKNZ 2020-01130).