Clinical Burden of Pediatric Influenza A and B in Malaysia: Outcomes and Resource Utilization in A Tropical Setting.

Background: Influenza is a leading cause of pediatric respiratory illness globally, yet comparative data on influenza A and B in tropical regions remain scarce. This study aimed to compare clinical features, healthcare utilization, and outcomes in children hospitalized with laboratory-confirmed influenza A and B.

Materials and methods: We conducted a retrospective cross-sectional study of children aged ≤12 years hospitalized with laboratory-confirmed influenza at a tertiary referral centre from May 2022 to December 2023. Influenza diagnosis was established using antigen-based detection via direct fluorescent antibody testing. Demographics, clinical features, laboratory results, interventions received, and patient outcomes were analyzed.

Results: Among 177 hospitalized children, 116 (65.5%) had influenza A and 61 (34.5%) had influenza B. Seizures were significantly more common in influenza A (27.6% vs. 3.3%, P<0.001). Influenza B was associated with higher rates of diarrhea (31.1% vs. 14.7%, P=0.010) and signs of respiratory distress (tachypnea: 42.6% vs. 26.7%, P=0.031; chest recessions: 41.0% vs. 25.0%, P=0.028; adventitious breath sounds: 45.9% vs. 29.3%, P=0.028). Children with influenza B more frequently required non-invasive ventilation (13.1% vs. 3.4%, P=0.015), and intravenous fluids (70.5% vs. 55.2%, P=0.048). Median hospital stay was longer in influenza B (3 vs. 2 days, P=0.008).

Conclusion: Influenza A was more frequently associated with neurologic manifestations, whereas influenza B showed a higher prevalence of lower respiratory and gastrointestinal symptoms and required greater supportive care. These findings highlight the distinct clinical profiles of influenza A and B and their implications for healthcare resource utilization.