Predictors of Post-COVID-19 Syndrome (Long COVID) In the Pediatric Population: A Retrospective Case–Control Study

Lica MO, Tinciu IF, Draganesciu AC and Plesca DA

Published on: 2026-04-13

Abstract

Long COVID in children is increasingly recognized, yet its clinical predictors and biological correlates remain insufficiently defined. This study aimed to compare clinical, demographic, and laboratory characteristics between children with and without long COVID and to identify factors associated with persistent symptoms.

We conducted a retrospective case–control study at a tertiary pediatric hospital, including children with confirmed SARS-CoV-2 infection. Cases were defined as patients with symptoms persisting for at least 12 weeks after acute infection, while controls had complete resolution of symptoms by this time point. Clinical data, demographic variables, and laboratory parameters were analyzed, and a multivariate predictive model was developed to assess factors associated with long COVID.

A total of 89 children with long COVID and 88 matched controls were included. Children with long COVID were significantly older and more frequently from urban areas. Laboratory findings revealed lower lymphocyte, monocyte, and basophil counts, along with higher levels of D-dimer, ferritin, serum iron, urea, and creatinine. The predictive model demonstrated excellent discrimination, with an area under the curve of 0.94 and high sensitivity and specificity at the optimal probability threshold.

Long COVID in children is associated with distinct clinical and biological features, suggesting that persistent symptoms may reflect measurable systemic alterations. These findings highlight the potential role of combined clinical and laboratory markers in early risk stratification and targeted follow-up. Further validation is required, but this study provides clinically relevant insights that may improve the management and monitoring of pediatric patients with post-COVID conditions.