Background: Parkinson’s disease (PD) is a neurodegenerative disease. Immune response varies after vaccination in different patients. We aimed to evaluate interferon beta-1b (IFNβ-1b) level in patients with PD in response to inactivated SARS-CoV-2 (CoronaVac) vaccination.Methods: Eight patients with the diagnosis of idiopathic PD and followed in the outpatient clinic (stages 1-2) were enrolled. Total blood count was performed before vaccination. IFNβ-1b levels were measured by ELISA and motor examination was performed before and two hours after vaccination.Results: IFNβ-1b levels increased in three patients, whereas no change was detected in one patient and the levels decreased in four patients. Divergent responses were found related to the time of diagnosis.Conclusion: The time of PD diagnosis, as well as the age of the patients, may be responsible for the variability of the post-vaccine immune response