A Comparison of the Clinical and Laboratory Characteristics of Influenza A and B Infections in Children

Aim: In this study, we aimed to compare the clinical and laboratory findings of Influenza A and Influenza B infections in children. Methods: The study included 1826 pediatric patients (aged <16 years) who were di¬agnosed with Influenza A (n=1400) and B (n=426) infections between 1 October 2019 and 30 April 2020. The patients were also divided into age groups: the age groups of 0–2 years, 3–9 years, and 10–16 years. The characteristic clinical and laboratory findings were compared. Results: Influenza A infection was significantly more common in patients aged <2 years and was significantly less common in patients aged 3–9 years. Body temperature was significantly higher in all age groups with Influenza A infection than in children with Influenza B infection. While leukocy¬tosis and lymphopenia were significantly more common in the Influenza A group, leukopenia and neutropenia were significantly more common in the Influenza B group. While acute otitis media was more common in Influenza A infection, myositis was more common in Influenza B infection. No significant difference was found between the Influenza A and B groups in terms of hospitalization rates. Of all patients, 98.3% were treated with oseltamivir. Conclusion: Our findings indicate that Influenza A and B infections are, in general, very similar in terms of symptoms. However, Influenza A infection is more common in very young children. It progresses with higher fever and is more frequently associated with pharyngeal hy¬peremia and acute otitis media, while leukopenia, neutropenia, conjunctivitis, nasal discharge, and myositis were found to be more common in Influenza B infection.