A 13-Year Retrospective Study of Disease Patterns of Adenoviral Keratoconjunctivitis at a Tertiary Hospital in Switzerland (2012–2025)

To report epidemiological patterns of adenoviral keratoconjunctivitis at a tertiary care hospital in Switzerland from 2012 until 2025, particularly comparing incidence rates during the COVID-19 pandemic. A single-centre, retrospective, observational study including all patients diagnosed with adenoviral keratoconjunctivitis from May 2012 until March 2025, describing patients’ demographics (gender, age), analysing and comparing incidence rates prior, during and after the COVID-19 pandemic. All cases were diagnosed with PCR testing and/or the AdenoPlus® test. During the COVID-19 pandemic, incidence rates of Adenovirus keratoconjunctivitis dropped from a mean number of 1.15 (SD ± 1.27, range: [0–6]) cases per month down to 0.57 (SD ± 0.79, range: [0–2]) during the COVID-19 pandemic. Overall incidence rates showed seasonal fluctuations, with most infections occurring in autumn months. Furthermore, demographic analysis revealed a significant gender disparity with higher male incidence (male:female ratio 1.39:1). During the quarantine measures of the COVID-19 pandemic, incidence of laboratory-confirmed Adenovirus keratoconjunctivitis was significantly reduced, which might be associated with social distancing and increased hygiene measures. After cessation of quarantine measures, incidence rates returned to pre-pandemic levels. This study provides insight into epidemiological patterns of Adenovirus keratoconjunctivitis while emphasising the importance of hygiene measures in preventing diseases.