Seasonality of Herpes zoster and Herpes zoster ophthalmicus in Germany – a 14-year Single Centre Study

Background While the incidence of herpes zoster has been reported to exhibit seasonal patterns in different global regions, with some studies suggesting correlations with weather data, data specific to Germany has been lacking. We investigated the seasonality of herpes zoster incidence in Germany and compared weather data. Patients and methods We conducted a single centre, interdisciplinary retrospective analysis of all herpes zoster cases at the Department of Dermatology and the Eye Centre from the Medical Centre, University of Freiburg from January 1st 2009 to December 31st 2022. 2,829 patients were identified using ICD-10 code B02.0 – 9. Monthly and cumulative daily incidences were calculated and plotted. Weather data were compared, including mean monthly temperature, sunshine duration, and UV-index. Results The analysis revealed two distinct incidence peaks: a summer peak correlating with weather factors, and an unexpected winter peak from late December through early January that did not correlate with the investigated weather parameters. Conclusions Our findings suggest that weather factors, like temperature, and UV-index, influence the incidence of herpes zoster in Germany. The previously undescribed “new year spike” indicates that additional, non-meteorological factors may trigger herpes zoster reactivation. This study provides insights into herpes zoster epidemiology in Germany and highlights the need for further research into trigger factors.