Hospitalized children with influenza A before, during and after COVID-19 pandemic: a retrospective cohort study.

Context: Since the outbreak of COVID-19 in late 2019, the transmission dynamics and clinical presentation patterns of influenza A (Flu A) virus have undergone changes.
Objectives: This article conducted a comparative analysis in clinical characteristics and laboratory results of pediatric patients with Flu A before, during, and after the COVID-19 pandemic.
Methods: The medical records of 885 children hospitalized with Flu A virus infection at a tertiary hospital in Guangdong Province, China, were retrospectively analyzed. Flu A was confirmed in these cases using a direct immunofluorescence antigen assay. The clinical data for this study span from January 1, 2018, to May 31, 2023.
Results: In our study, we observed a total of 340 cases before the COVID-19 pandemic, 196 cases during the pandemic, and 349 cases after the pandemic. Patients after the pandemic had a higher median age on admission (5.66 years, range 3.41-7.70) and exhibited more respiratory symptoms such as cough, sore throat, and nasal stuffiness. The length of hospital stay was longer, and there was a higher percentage of patients with fever duration ≥ 5 days among Flu A patients during the pandemic. Compared to before and during the COVID-19 pandemic, Flu A patients after the pandemic showed significantly reduced white blood cell (WBC) and platelet (PLT) counts (P < 0.001), along with elevated levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in laboratory indexes (P < 0.001). Furthermore, more hospitalized children after the pandemic were diagnosed with benign acute childhood myositis (BACM).
Conclusion: Our research results indicates a significant decrease in Flu A cases during the COVID-19 pandemic, and hospitalized children with Flu A have more severe clinical symptoms after the COVID-19 pandemic. These findings have implications for public health policy and clinical management of Flu A cases.
Clinical Trial Number: Not applicable.
Competing Interests: Declarations. Ethics approval and consent to participate: The studies involving humans were approved by the Institute Ethics Committee of Chaozhou Central Hospital (No. 2023009) and People’s Hospital of Yangjiang (No. 20230003). The studies were conducted in accordance with the local legislation and institutional requirements. The Ethics Committee/Institutional Review Board waived the requirement of written informed consent for participation from the participants or the participants’ legal guardians/next of kin. Competing interests: The authors declare no competing interests.
(© 2024. The Author(s).)