The Clinical Burden of SARS-CoV-2 Compared to Influenza A in the Same Cohort of Paediatric Outpatients; Increased Influenza Severity and Potential Insights.

INTRODUCTION: The variation in the clinical severity of viral infections remains a matter of scientific debate. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and Influenza A virus (IAV) are both RNA viruses, exhibiting a range of clinical presentations, ranging from asymptomatic cases to fatalities, influenced by both viral and host factors. A descriptive real-life study was conducted, aiming to compare the clinical manifestations of recent COVID-19 with those of IAV infection in the same group of non-hospitalised, unvaccinated children.

MATERIALS AND METHOD: Between September 2021 and February 2023, we evaluated 115 individuals (male 48.7%, mean age 101.8 ± 50.8 months) who had not received vaccination for both SARS-CoV-2 and the quadrivalent influenza vaccine and were documented to be infected with both viruses within a 12-month time interval. The visual analogue scale (VAS-5) was used to assess parents'/patients' evaluation comparing the two infections.

RESULTS: In cases of IAV infection, a significantly higher prevalence of prolonged high fever, upper and lower respiratory symptoms, and secondary infections was observed. The majority (74.8%) of patients and/or parents assessed IAV as a more severe clinical syndrome compared with SARS-CoV-2.

CONCLUSIONS: The clinical burden of IAV was found to be greater than that of SARS-CoV-2 infection in the same unvaccinated children. This variation in clinical severity may provide a reference for effective vaccination policies; however, underlying mechanisms that could explain this difference require further evaluation.