In March 2021 several cases of cerebral venous sinus thrombosis (CVST) accompanied by thrombocytopenia were reported that occurred within two weeks after immunization with a viral vector-based COVID-19 vaccine. This study aimed to assess the background incidence of CVST and CVST with concurrent thrombocytopenia in adults using anonymized claims data from 2015-2019 in Germany. The average annual CVST incidence was 1.9 per 100,000 individuals (95%-CI 1.4-2.3). It was higher in women aged 18 to 59 years as compared to same-aged men. In contrast to the currently reported immunization-related cases, CVST was rarely associated with concurrent thrombocytopenia or death.