Epidemiological, Clinical and Laboratory Characteristics of Hospitalized Children with SARS-CoV-2 Infection During Three Consecutive Pandemic Years: A Retrospective Cohort Study

Abstract

Background: Coronavirus disease 2019 (COVID-19) generally follows a milder clinical course in children than in adults. The clinical characteristics of pediatric severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have evolved throughout the pandemic and longitudinal data comparing successive pandemic years remain limited. Objective: To compare the epidemiological, clinical, and laboratory characteristics of children hospitalized with SARS-CoV-2 infection during 2020–2022 and to identify factors associated with disease severity. Methods: We conducted a retrospective cohort study of children aged 1 month to 18 years hospitalized with laboratory-confirmed SARS-CoV-2 infection at a tertiary pediatric hospital in Bucharest, Romania, between January 2020 and December 2022. Results: Of 669 eligible patients, 519 met the inclusion criteria (118 in 2020, 168 in 2021, and 233 in 2022). The proportion of hospitalized infants increased over time, whereas adolescent admissions declined (p < 0.001). Respiratory manifestations remained predominant, while gastrointestinal involvement was consistently common. Respiratory manifestations increased from 61.9% in 2020 to 77.3% in 2022 (p = 0.01), while gastrointestinal manifestations remained consistently frequent. Cardiovascular manifestations were reported in 28.9% of patients, without significant differences across the study years (p = 0.06). Neuromuscular manifestations declined from 43.2% in 2020 to 12.0% in 2022 (p < 0.001). Leukocyte count, lymphocyte count, and hemoglobin differed significantly across the study period, whereas C-reactive protein remained unchanged. Moderate-to-severe disease was associated with digestive, cardiovascular, and reno-urinary involvement but not with sex or residence. Conclusions: The epidemiological and clinical profile of hospitalized children with SARS-CoV-2 infection changed substantially across the first three years of the pandemic. These findings highlight the importance of continued surveillance and comprehensive clinical assessment to optimize the management of pediatric COVID-19.