Introduction
Coronavirus Disease 2019 (COVID-19) is an infectious disease with a rapid increase in cases and deaths since its first identification in Wuhan, China, in December 2019. The virus that causes COVID-19 is designated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Sore throat, high fever, shortness of breath, dry cough, headache, confusion, nausea, vomiting, diarrhea or loss of taste/smell are the most common manifestations of the disease (1, 2). COVID-19 testing includes either the detection of the virus itself by real-time reverse transcription polymerase chain reaction or those antibodies produced in response to infection (3). COVID-19 is predominantly prevalent among adults; patients under 18 years only account for 2% of the severely affected patients (4, 5).
Quantitative changes in blood cells, including leukocytes, lymphocytes, neutrophils, monocytes and platelets, have been reported in adults patients with COVID-19 (2, 6-8); moreover, the extent of such quantitative changes has been correlated with the severity of the disease in adults (6, 9). Normal (10), decreased (11) and increased (8) leukocyte counts have been reported. In general, decreased lymphocyte (11, 12) and increased neutrophil (2, 9, 13), counts have been noted in various studies. However, there is paucity of data on the hematologic parameters of children with COVID-19 (4). In a review article on COVID-19 in children, a Chinese article was quoted reporting that “the most routine blood examinations were normal” (4). In another study reporting 10 pediatric patients affected with the disease, “a few cases” were reported to have leukopenia and lymphopenia (14). Moreover, although the morphological changes in peripheral blood cells have been reported in adults with COVID-19 (15), such changes, to our knowledge, have not been reported in children affected with the disease .
The aim of this retrospective study is to report the quantitative and qualitative changes of peripheral blood cells in children with COVID-19 and compare them with those of symptomatic children suspected but then confirmed to be negative for SARS-CoV-2.