COVID-19 vaccines and attributable risk of neurological disorders: a multicentre, case-control study (COVIVAX)

Abstract The COVIVAX study investigated the attributable risk of common neurological disorders in previously neurologically-healthy persons exposed to COVID-19 vaccines. In a multicenter, case-control study, the proportions of individuals with a first diagnosis of a neurological disorder (cases) and controls were compared in vaccinated versus unvaccinated participants. A total of 624 participants were enrolled. The most frequent neurological diagnosis in cases were stroke (60.4%), multiple sclerosis (11.3%) and seizures (6.4%). The risk of developing a new neurological disorder was reduced in vaccinated participants, compared to unvaccinated ones (OR 0.50; 95% CI 0.29–0.86; p = 0.0114). The number of doses received was associated with a reduced risk of developing new neurological disorders for participants aged over 60 years ( p = 0.0472; OR 0.14, 95% CI 0.03–0.68), with pre-existing comorbidities (p = 0.0122; OR 0.04, 95% CI 0.01–0.99) and for stroke (p = 0.0232; OR 0.04, 95% CI 0.02–0.97). The COVIVAX study provided no warning sign regarding the risk of developing new neurological disorders following COVID-19 vaccination of any type or doses. A potentially protective effect of multiple doses of COVID-19 vaccines against the risk of stroke in people aged over 60 needs to be confirmed by further studies.