Children and Adolescents Hospitalized With COVID-19 in a University Hospital in Greece 2020-2024

To compare the characteristics, manifestations and outcome of children hospitalized with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection according to the dominant variant period.

We prospectively studied children 0-17 years with SARS-CoV-2 infection hospitalized for acute symptoms during 2020-2024. Multivariable logistic regression models were applied to estimate the association between variables, including onset of symptoms, fever and lower respiratory tract infection (LRTI).

We studied 726 children (mean age: 3.3 years), including 81 (11.2%) with ≥1 underlying condition. Fever was the most prevalent symptom (75.1%) throughout the study; LRTI occurred in 6.9% of children. All children had a favorable outcome, and no case of mechanical ventilation or death occurred. Thirty-two children (4.4%) were admitted during the ancestral period, 45 (6.2%) during the Alpha variant, 123 (16.9%) during the Delta variant, and 526 (72.5%) during the Omicron variant periods. Children admitted during the ancestral period were less frequently symptomatic and/or febrile than those admitted in subsequent dominant variant periods ( P value ≤ 0.001). Fever occurred more often at ages 3-11 months, 1-2 and 3-12 years, as compared with age 0-2 months and among children hospitalized during the Delta variant period as compared with those hospitalized in the ancestral period. Children with underlying conditions were more likely to develop LRTI as compared with children with no underlying conditions.

Approximately 3 of 4 SARS-CoV-2 childhood admissions occurred during the Omicron period. Only a few cases of LRTI occurred, mostly among children with underlying conditions. All hospitalized children had a favorable outcome.