Bell's palsy and COVID-19 vaccination: a systematic review

Abstract

Bell's palsy is a rare side effect reported in COVID-19 vaccines. Given the importance of neurological manifestations, the necessity to highlight and analyze the incidence of them after COVID-19 vaccination is needed. This study aimed to systematically review the reported cases of Bell's palsy following vaccination against COVID-19. Search method: This systematic review is implemented based on the Cochrane Collaboration Handbook and PRISMA Statement (Preferred Reporting Items for Systematic Reviews and Meta-Analyzes), and the proposed systematic review was conducted following the Joanna Briggs Institute (JBI) methodology for systematic reviews. The inclusion criteria for the included published studies were patient age ≥18 years; history of Bell's palsy post-COVID-19 vaccination and proved diagnosis in the patients with COVID-19 vaccination. The exclusion criteria for the studies were duplicate studies that included repetition of cases and studies with missing clinical data . The search strategy aimed to find both published and unpublished studies in August 2021 and updated by hand searching using the identified keywords and index terms in Cochrane Library, MEDLINE (PubMed), Web of Science, Scopus, ProQuest, and Google scholar in May 2022 . Finally, the reference lists of all identified reports and articles were searched for more studies. The JBI critical appraisal tools for case reports or case series were used to determinate the risk of bias in the included studies. Results: During the electronic search, manual search, and reference check, we found 1281 citations, and in hand searching, we detected additional 15 studies. After discarding duplicated citations, and evaluating the title, abstract, and full text 15 case-report and two case-series studies were included for the critical appraisal process and were included in this study. Pfizer and Moderna vaccines were the most common vaccines among studies that revealed the cases of Bell’s palsy. Paralysis of left side was more common than right-sided paralysis. The interval between vaccination and the manifestations of Bell's palsy (facial weakness) was between 1 and 48 days.