Seasonality Disrupted: Post-Pandemic Trends in Otorhinolaryngological Infections

Background: The COVID-19 pandemic has notably affected the epidemiology of various infectious diseases. The imposed public health measures and disruptions in vaccination programs have potentially altered the patterns of these diseases post pandemic. Objective: To investigate the change in epidemiology of otorhinolaryngological infectious diseases in adult and pediatric patients after the COVID-19 pandemic and the relaxation of public health measures. Methods: A retrospective cohort study was conducted at a large tertiary university otolaryngology department in the south of Germany, examining admissions with specific ICD-10 diagnoses from 2019 to 2023. Data were seasonally categorized and statistically analyzed. Results: A total of 1728 inpatient cases were analyzed. There was a significant increase in otorhinolaryngological infections in the post-pandemic winter of 2022, particularly of peritonsillar abscesses, acute tonsillitis and acute mastoiditis. No significant post-pandemic spike in mononucleosis was observed. The duration of hospitalization was shorter in 2022, and the median age of patients did not change significantly pre- versus post-pandemic. Conclusions: The study indicates a significant post-pandemic rise in otorhinolaryngological infections. Remarkably, the typical "dip" in infections during the summer months was not observed in the post pandemic years, possibly reflecting the impact of the termination of non-pharmaceutical interventions. Mononucleosis was the only infection not following this pattern.