Clinical Characteristics, Seasonality, and Management of Pediatric Influenza Infection During and After the COVID-19 Pandemic: A Retrospective Study from Saudi Arabia

Background Influenza remains a major cause of acute respiratory illness in children worldwide. Following the COVID-19 pandemic, significant changes in respiratory virus circulation have been observed, with a resurgence of influenza activity. Data describing pediatric influenza characteristics during this period in Saudi Arabia remain limited. This study aimed to describe the clinical features, seasonal trends, diagnostic practices, and management of laboratory-confirmed pediatric influenza infection during and after the COVID-19 pandemic. Methods A retrospective observational study was conducted at King Faisal Specialist Hospital and Research Centre, Riyadh. Medical records of children aged ≤ 15 years with polymerase chain reaction (PCR)–confirmed influenza infection between January 2019 and April 2024 were reviewed. Demographic characteristics, comorbidities, influenza subtypes, co-infections, investigations, management strategies, hospitalization, and complications were analyzed descriptively. Results A total of 138 children were included, with a median age of 5.23 years (IQR 5.79); 48.6% were younger than five years, and 62.3% were male. Comorbidities were present in 68.1% of cases, most commonly bronchial asthma (53.2%). Influenza A/H3 was the predominant subtype (55%). Viral co-infections were identified in 38% of cases, most frequently rhinovirus (17.4%). Influenza activity was minimal between 2019 and mid-2021, followed by a marked resurgence peaking in mid-2022. Additional investigations were frequently performed, including chest radiographs (44%), although clinically significant abnormalities were uncommon. Most patients (87.6%) were managed on an outpatient basis; only 12.3% required hospitalization. Supportive care was the most common treatment approach, followed by antiviral therapy. Complications occurred in 8% of cases. Conclusion Pediatric influenza predominantly affected young children with underlying comorbidities and generally followed a mild clinical course. The post-pandemic resurgence of influenza highlights the importance of preventive strategies, judicious use of diagnostic investigations, and continued emphasis on influenza vaccination in pediatric populations. The study was approved by the Institutional Review Board of King Faisal Hospital and Research Centre (|KFSHRC). Approval No. 2251461.