Abstract
BACKGROUND AND PURPOSE: The purpose of this study was to evaluate the possible correlation between SARS-CoV-2 vaccines and the onset of neurological syndromes. The aim was to challenge the association between SARS-CoV-2 vaccinations and the onset of acute functional neurological disorders (FNDs) compared to other neurological syndromes in hospitalized patients. METHODS: In this prospective cohort study, all adult inpatients consecutively admitted to a tertiary neurological centre were included. The prevalence and characteristics of neurological syndromes were compared between unvaccinated and vaccinated cases stratified according to the onset from vaccination. The study involved 843 subjects, namely 411 unvaccinated (UVC) and 432 vaccinated cases; these groups were comparable for demographics and clinical diagnosis distribution. RESULTS: Compared to UVC, subjects hospitalized within the first 30 days from vaccine exhibited higher prevalence of FNDs (12.3% vs. 3.6%; odds ratio 4.2, 95% confidence interval 1.6-11.1) and headache (10.8% vs. 5%; odds ratio 4.1, 95% confidence interval 1.9-8.8) but no other neurological syndromes. The FND cases following vaccinations showed similar premorbid conditions and severity but a higher percentage of sensory symptoms and pain compared to UVC FND cases. CONCLUSIONS: SARS-CoV-2 vaccination is associated with a significant short-term increased risk of FND and headache requiring hospitalization in an acute neurological setting.