Risk and characteristics of attacks occurring after vaccination in patients with neuromyelitis optica spectrum disorders: A systematic review and meta-analysis.

ABSTRACT

BACKGROUND: Vaccination in patients with neuromyelitis optica spectrum disorders (NMOSD) is challenging because there is a concern that vaccines can lead to clinical attacks. However, little is known about the risk and the characteristics of attacks occurring after vaccination. METHODS: We performed a systematic review and meta-analysis using PubMed and Embase databases to estimate a summary frequency of attacks occurring after vaccination and describe the clinical features of theses attacks. We defined attacks occurring after vaccination as typical NMOSD attacks that occurred up to 30 days after vaccine administration.  For the frequency of attacks occurring after vaccination, we selected observational studies that reported the number of attacks and total number of patients that received vaccines; for the clinical description of the attacks, case reports and case series were also included. RESULTS: We included 377 participants from 5 studies to estimate the frequency of NMOSD attacks occurring after vaccination. We found a summary frequency of of 2% (95% CI 1-4%, I2 = 0%). We evaluated 17 studies to identify that 13 different vaccines were associated with NMOSD attacks. A higher-than-expected proportion of males, simultaneous optic neuritis and transverse myelitis attacks, and anti-aquaporin 4 antibody negative cases were identified in vaccine-associated attacks from 24 participants from 17 studies. Nearly two-thirds of attacks occurring after vaccination were an initial event of NMOSD. CONCLUSION: The frequency of NMOSD attacks occurring after vaccination is low and non-specific to different vaccine technologies. Our work reinforces the safety of vaccine recommendations in patients with NMOSD.