Hematological profile of COVID-19 infected children before and after the spread of the Omicron variant in Istanbul

Abstract

Objective: To examine the effect of the COVID-19 virus, especially the Omicron variant, on hematological parameters of hospitalized pediatric patients during the COVID-19 pandemic. Methods: Medical records of pediatric COVID-19 patients hospitalized at Kartal Dr. Lütfi Kirdar City Hospital in Istanbul, Turkey, between March 2020 and May 2022 were retrospectively reviewed to analyze data regarding demographics, SARS-CoV-2 infection polymerase chain reaction (PCR) test results, reverse-transcriptase (RT)-PCR for other respiratory agents, duration of hospital stay, and hematological and biochemical laboratory findings. Results: Out of 467 children with a confirmed diagnosis of SARS-CoV-2 infection, 94 (20.1%) had Omicron infection and 373 (79.9%) were infected with other variants; the Omicron group had younger patients than the remaining samples (P<0.001). The most frequent clinical symptoms in all children were cough (53.5%) and fever (32.3%), followed by vomiting (20.8%). Lung involvement in the Omicron group (10.6%) was significantly lower than in the remaining samples (29.8%) (P<0.001). Hemoglobin and lymphocyte levels were lower in the Omicron-infected group (both P<0.001), while prothrombin time, activated partial thromboplastin time, international normalized ratio, and D-dimer levels were significantly higher in this group (P<0.001, P<0.001, P<0.001, and P=0.023, respectively). In terms of lung involvement, those with lung involvement were significantly older (P<0.001). Conclusions: Although lung involvement was less common with Omicron infection, this group had greater hematological system involvement, such as anemia, lymphopenia, D-dimer elevation, and coagulation disorders.