Incidence and characteristics of post-COVID-19 parkinsonism and dyskinesia related to COVID-19 vaccines

Background: Coronavirus disease 2019 (COVID-19) is an infectious disease mainly affecting the respiratory system; however, a significant prevalence of neurological symptoms has been noted.

Objectives: To investigate the incidence and characteristics of post-COVID-19 parkinsonism and to study dyskinesia related to COVID-19 vaccines.

Material and methods: The MEDLINE, PubMed, Scopus, and Web of Science databases were searched for all manuscripts relevant to post-COVID-19 parkinsonism and dyskinesia related to COVID-19 vaccines. Subsequently, we extracted and analysed data from the manuscripts in a structured manner.

Results: We found 24 patients with post-COVID-19 parkinsonism, with a mean onset age of 58 years after a mean of 30 days from the COVID-19 onset. Akinetic-rigid (n = 11) and mixed (n = 6) subtypes were the most common. Asymmetry was present in 13/15 patients. Brain MRI was unremarkable in 11/19, whereas dopaminergic system imaging was abnormal in 8/8 patients. Responsiveness to dopaminergic treatment was observed in 12/15 patients. Four patients improved after immunomodulatory therapy. Comorbidities were present in 9/24, encephalopathy symptoms in 11/24, and loss of smell in 9/13 patients. Most patients (n = 14) suffered serious COVID-19- related complications and three were treated with haloperidol. Parkinsonism improved (n = 5) or resolved (n = 4) during the follow-up. Five patients, with a mean age of 52, developed dyskinesia at a mean of 25 hours after receiving the COVID-19 mRNA vaccines. One patient had a history of neuropsychiatric symptoms and developed functional dyskinesia of the tongue. Four patients had a previous history of Parkinson's Disease (PD) with a mean duration of 10 years and developed dyskinesia and dystonia, which resolved (n = 2) or improved (n = 2) during the follow-up.

Conclusions: Post-COVID-19 parkinsonism is a very rare complication, and it is likely that this is an umbrella syndrome that includes many different etiologies. Dyskinesia due to COVID-19 vaccines is exceedingly rare and probably has the same pathophysiological basis as in other conditions with exacerbation of PD symptoms.