Comparative study on blood routine test and inflamatory makers of COVID-19 and influenza A virus infection in infants

doi:10.3969/j.issn.1674-490X.2026.02.003

Abstract

Abstract: Objective To explore the differences in early blood routine indicators, including white blood cell count, neutrophil count, lymphocyte count, platelet count, C-reactive protein, serum amyloid A, procalcitonin, and neutrophil-to-lymphocyte ratio, between infants with novel coronavirus infection(COVID-19)and those with influenza A virus infection(IAV). Methods A comparative analysis was conducted on inflammatory blood indicators in 63 COVID-19 patients and 69 IAV patients admitted to Intensive Care Unit of Beijing Children's Hospital from January 1 to March 31, 2025. Results The white blood cell count in 63 children with COVID-19 was(5.12±1.89)×10⁹·L^-1, which was lower than that in 69 children with IAV(5.92±2.12)×10⁹·L^-1, with a statistically significant difference(t=-2.291,P=0.016). The neutrophil count in 63 children with COVID-19 was 2.30(1.62, 3.43)×10⁹·L^-1, which was lower than that in 69 children with IAV(2.71(1.43, 3.93)×10⁹·L^-1), with a statistically significant difference(Z=-2.540,P=0.011). The neutrophil-to-lymphocyte ratio in 63 children with COVID-19 was 0.98(0.62, 1.86)×10⁹·L^-1, which was lower than that in 69 children with IAV(1.29(0.48, 2.85)×10⁹·L^-1), with a statistically significant difference(Z=-2.882,P=0.004). The platelet count in 63 children with COVID-19 was(278.31±80.10)×10⁹·L^-1, which was higher than that in 69 children with IAV(233.51±74.21)×10⁹·L^-1, with a statistically significant difference(t=3.323,P<0.001). The C-reactive protein level in 63 children with COVID-19 was 4.23(0.50, 7.72)mg·L^-1, while that in 69 children with IAV was 3.12(0.50, 6.22)mg·L^-1, with statistically significant difference between the two groups(Z=-2.002, P=0.045). The serum amyloid A levels in 63 children with COVID-19 were 15.32(3.01, 19.70)mg·L^-1, while those in 69 children with IAV were 9.45(1.00, 12.00)mg·L^-1. There was statistically significant difference between the two groups(Z=-2.649, P=0.008). Conclusion The white blood cell count, neutrophil count, and neutrophil-to-lymphocyte ratio in the COVID-19 group are significantly lower than those in the IAV group. Platelet count, serum amyloid A, and C-reactive protein are significantly higher in the IAV group. There are characteristic differences in peripheral blood inflammation and platelet-related indicators between pediatric COVID-19 and IAV infections. Elevated white blood cell count, neutrophil count, and neutrophil-to-lymphocyte ratio accompanied by reduced platelet count are laboratory features of IAV infection and can serve as important laboratory references for clinical differential diagnosis between the two viral infections.

Key words: infants and young children, respiratory infections, SARS-CoV-2, influenza A virus, inflammatory markers

CLC Number:

YANG Mei, HAN Yanli, CHEN Xin. Comparative study on blood routine test and inflamatory makers of COVID-19 and influenza A virus infection in infants[J]. Journal of Hebei Medical College for Continuing Education, 2026, 43(2): 20-25.

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