The longitudinal evaluation of COVID-19 in pediatric patients and the impact of delta variant.

BACKGROUND: Pediatric patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) displayed milder symptoms than adults. However, they play an important role in case numbers and virus transmission. Therefore, we aimed to determine the epidemiological features of all pediatric patients infected with SARS-CoV-2 and put forth case numbers longitudinally throughout the delta variant dominant period. METHODS: A retrospective study was conducted at a university hospital and included patients between 0 and18 years old with a SARS-CoV-2 polymerase chain reaction (PCR) positive result, including inpatients and outpatients. Epidemiological and clinical features were recorded from electronic files, and telephone visits were performed between March 2020 and December 2021. RESULTS: During the study period, 3175 coronavirus disease 2019 (COVID-19) pediatric patients were admitted to our hospital with a mean age of 10.61 ± 4.6 years. Of the 1815 patients who could be interviewed, 85.7% reported at least one symptom. Before the delta variant period, 0-4 years aged children were more commonly infected, while school-aged children and adolescents were more common, and the rate of pediatric cases to all COVID-19 cases increased to 35.8% after the delta variant became dominant. Symptomatic cases were significantly higher before the delta variant (87.8% vs. 84.06%, p = 0.016). The hospitalization rate was higher before the delta variant (p < 0.001), whereas PICU admission showed no statistical difference. CONCLUSIONS: The frequency of school-aged children and adolescents raised with the impact of both school openings and the delta variant, and the rate of pediatric cases increased in total COVID-19 patient numbers.