Background: SARS-CoV-2 infection has been extensively documented since the onset of the pandemic, particularly in the adult population. However, there is a lack of evidence describing the phenotypic manifestations of the disease in the pediatric population. We aimed to characterize the clinical phenotypes of SARS-CoV-2 infection in hospitalized children. Methods: The EPICO study is a multicenter cohort conducted between April 2020- November 2021, involving 55 institutions in Spain and 13 institutions in Colombia. Hospitalized children aged 29 days to 17 years with confirmed SARS-CoV-2 infection were included to determine the disease´s evolution, severity factors, and outcomes. Cluster analysis was conducted to characterize clinical phenotypes. Results: A total of 2318 patients from Colombian and Spanish institutions were included. The population was 55% male, with infants being the largest group (36%). Five distinct phenotype clusters emerged, differing significantly in clinical and epidemiological characteristics. Cluster 1 (26.57%) consisted of infants without comorbidities, with low PICU admission and mortality rates. Cluster 2 (18.5%) had respiratory comorbidities, high co-detection, and mortality rates. Cluster 3 (11.51%) showed fever, gastrointestinal symptoms, and high PICU admission. Cluster 4 (32.09%) had mild unspecific symptoms and low mortality. Cluster 5 (11.3%) included adolescents without comorbidities, with low co-detection and hospitalization rates. Comparable findings were observed in both countries. Conclusion: Our study successfully identified distinct patterns of clinical and epidemiological characteristics associated with SARS-CoV-2 infection in hospitalized pediatric patients. These findings may help shape future guidelines and improve risk stratification in children.

Pneumonia is a frequent manifestation of COVID-19 in hospitalized children. Methods The study involved 80 hospitals in the SARS-CoV-2 Spanish Pediatric National Cohort. Participants were children <18 years, hospitalized with SARS-CoV-2 community-acquired pneumonia (CAP). We compared the clinical characteristics of SARS-CoV-2-associated CAP with CAP due to other viral etiologies from 2012 to 2019. Results In total, 151 children with SARS-CoV-2-associated CAP and 138 with other viral CAP included. Main clinical features of SARS-CoV-2-associated CAP were cough 117/151(77%), fever 115/151(76%) and dyspnea 63/151(46%); 22/151(15%) patients were admitted to a pediatric intensive care unit (PICU), and 5/151(3%) patients died. Lymphopenia was found in 63/147(43%) patients. Chest X-ray revealed condensation (64/151[42%]) and other infiltrates (87/151[58%]). Compared with CAP from other viral pathogens, COVID-19 patients were older (8 vs.1 year; odds ratio [OR] 1.42 [95% confidence interval, CI 1.23;1.42]), with lower CRP levels (23 vs.48 mg/L; OR 1 [95%CI 0.99;1]), less wheezing (17 vs.53%; OR 0.18 [95%CI 0.11;0.31]) and greater need of mechanical ventilation, MV (7 vs.0.7%, OR 10.8 [95%CI 1.3;85). Patients with non-SARS-CoV-2-associated CAP had a greater need for oxygen therapy (77 vs.44%, OR 0.24 [95%CI 0.14;0.40]). There were no differences in the use of CPAP or HVF or PICU admission between groups. Conclusion SARS-CoV-2-associated CAP in children presents differently to other virus-associated CAP: children are older and rarely have wheezing or high CRP levels; they need less oxygen but more CPAP or MV. However, several features overlap, and differentiating the etiology may be difficult. The overall prognosis is good.