Reversible cerebral vasoconstriction syndrome and posterior reversible encephalopathy syndrome following vaccination: analysis of the VAERS database and systematic review

Objectives:This study aimed to analyze the Vaccine Adverse Event Reporting System (VAERS) database and systematically review the literature to provide a comprehensive analysis of reversible cerebral vasoconstriction syndrome (RCVS) and posterior reversible encephalopathy syndrome (PRES) secondary to vaccination.Methods:The authors analyzed the VAERS database and conducted a systematic review following PRISMA guidelines. The inclusion criteria for VAERS data were a score of >= 3 on the RCVS2 score and/or radiographic findings consistent with the diagnosis of RCVS or PRES. The systematic review was registered with PROSPERO.Results:Our combined data set included 29 cases (9 RCVS and 20 PRES). Most cases were women (72.4%) with a mean age of 50.7 years (SD 19.4 years). Most cases were associated with COVID-19 mRNA vaccines (58.6% Moderna, 20.7% Pfizer). Hypertension (37.9%), hyperlipidemia (13.7%), chronic kidney disease (CKD) (10.3%), and end-stage renal disease (6.8%) were common comorbidities. Furthermore, 20.6% (6/29) of cases were on immunosuppression therapy for various reasons. The mean time to symptom onset was 10.49 days after vaccination (SD 18.60), and the mean duration of hospitalization was 7.42 days (SD 5.94). The symptoms reported the most frequently were headache (41.3%), elevated blood pressure (31.0%), and emesis (17.2%). Typical radiographic findings included T2/FLAIR hyperintensities affecting the parieto-occipital lobes, indicative of vasogenic and/or cytotoxic edema.Conclusions:This study provides a comprehensive analysis of postvaccine RCVS and PRES. Both disease states were seen most often in those with pre-existing risk factors such as female sex, age over 50, hypertension, renal disease, and immunosuppression. Vaccines and their associated immune response may cause endothelial dysfunction leading to cerebral vasospasm and loss of cerebral autoregulation. However, further research is required to understand the underlying pathophysiological mechanisms. Despite the associations found, the absolute risk of these syndromes remains extremely low compared to the immense benefits of vaccination.