Neurological Immune-Related Adverse Events After COVID-19 Vaccination: A Systematic Review

ObjectiveThe goal of this study is to compile published data reporting neurological immune-related adverse events following COVID-19 vaccination, not including those relating to hematologic abnormalities such as thrombosis or hemorrhage.BackgroundCOVID-19 vaccination has been repeatedly shown to reduce the incidence and severity of COVID-19 infection. The expedited timeline of these vaccines has given rise to many discussions pertaining to their safety. Many neurological and non-neurological adverse events have been linked to COVID-19 vaccination including acute MI, anaphylaxis, appendicitis, Bell's palsy, deep vein thrombosis, disseminated intravascular coagulation, encephalomyelitis, transverse myelitis, and many others.Design/MethodsThe following databases were searched in April 2021 using different keywords: PubMed, Medline, Embase, Scopus, Web of Science, Science, Direct, MedRxiv, andLens.org. Studies were included if they reported any adverse immune-related neurological events secondary to COVID-19 vaccination. Studies were excluded if they were not in English, included self-reported events only, or did not report primary data. Screening and extraction were conducted by 2 different reviewers using Covidence.ResultsThe search strategy yielded 18 studies which reported a total of 61 patients who had received a COVID-19 vaccination and experienced = 1 neurological adverse events. Most reported adverse events were facial nerve palsy (52.5%), reactivation of herpes zoster (11.5%), Guillian-Barré syndrome (6.6%), demyelinating disease (6.6%), and neuropathy (11.5%). Other reported adverse effects were delirium, periauricular vesicular rash, bilateral sensorineural hearing loss, visual disturbance, gait disturbance, serotonin syndrome, and vestibular ataxia (16.4%).ConclusionsThe symptoms were time-limited and self-resolving in nature. In addition, the incidence of the reported events following COVID-19 vaccination compared to the general population is similar. Hence, there is little to no evidence suggesting a causal relationship between COVID-19 vaccination and neurological adverse events.