Observational Study of Patients Hospitalized With Neurologic Events After SARS-CoV-2 Vaccination, December 2020-June 2021

Background and Objectives The global spread of the COVID-19 pandemic accelerated the vaccine development time line, regulatory approval, and widespread implementation in the population underscoring the importance of postauthorization/postlicensure vaccine safety surveillance. To monitor for vaccine-related adverse events, we prospectively identified patients hospitalized for prespecified neurologic conditions who received mRNA or adenovirus COVID-19 vaccines and assessed cases for potential risk factors and alternative etiologies of the adverse event.Methods We identified prespecified neurologic conditions in hospitalized individuals within 6 weeks of receipt of a dose of any COVID-19 vaccination between December 11, 2020, and June 22, 2021 (Columbia University Irving Medical Center/New York Presbyterian Hospital, New York City, New York). Clinical data from electronic medical records in these vaccinated patients were reviewed for assessment of contributing risk factors and etiologies for these neurologic conditions by use of a published algorithm.Results Among 3,830 individuals screened for COVID-19 vaccination status and neurologic conditions, 138 (3.6%) cases were included in this study (126 after mRNA and 6 after Janssen vaccines). The 4 most prevalent neurologic syndromes included ischemic stroke (52, 37.7%), encephalopathy (45, 32.6%), seizure (22, 15.9%), and intracranial hemorrhage (ICH) (13, 9.4%). All 138 cases (100%) had 1 or more risk factors and/or evidence for established causes. Metabolic derangement was the most common etiology for seizures (24, 53.3%) and encephalopathy (5, 22.7%) while hypertension was the most significant risk factor in ischemic stroke (45, 86.5%) and ICH cases (4, 30.8%).Discussion All cases in this study were determined to have at least 1 risk factor and/or known etiology accounting for their neurologic syndromes. Our comprehensive clinical review of these cases supports the safety of mRNA COVID-19 vaccines.