Association of SARS-CoV-2 Vaccination or Infection with Bell Palsy: A Systematic Review and Meta-analysis

Abstract

Importance: Bell palsy (BP) has been reported as an adverse event following the SARS-CoV-2 vaccination, but neither a causative relationship nor a higher prevalence than in the general population has been established. Objective: To compare the incidence of BP in SARS-CoV-2 vaccine recipients vs unvaccinated individuals or placebo recipients. Data Sources: A systematic search of MEDLINE (via PubMed), Web of Science, Scopus, Cochrane Library, and Google Scholar from the inception of the COVID-19 report (December 2019) to August 15, 2022. Study Selection: Articles reporting BP incidence with SARS-CoV-2 vaccination were included. Data Extraction and Synthesis: This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline and was conducted with the random- and fixed-effect models using the Mantel-Haenszel method. The quality of the studies was evaluated by the Newcastle-Ottawa Scale. Main Outcomes and Measures: The outcomes of interest were to compare BP incidence among (1) SARS-CoV-2 vaccine recipients, (2) nonrecipients in the placebo or unvaccinated cohorts, (3) different types of SARS-CoV-2 vaccines, and (4) SARS-CoV-2-infected vs SARS-CoV-2-vaccinated individuals. Results: Fifty studies were included, of which 17 entered the quantitative synthesis. Pooling 4 phase 3 randomized clinical trials showed significantly higher BP in recipients of SARS-CoV-2 vaccines (77525 vaccine recipients vs 66682 placebo recipients; odds ratio [OR], 3.00; 95% CI, 1.10-8.18; I2= 0%). There was, however, no significant increase in BP after administration of the messenger RNA SARS-CoV-2 vaccine in pooling 8 observational studies (13518026 doses vs 13510701 unvaccinated; OR, 0.70; 95% CI, 0.42-1.16; I2= 94%). No significant difference was found in BP among 22978880 first-dose recipients of the Pfizer/BioNTech vaccine compared with 22978880 first-dose recipients of the Oxford/AstraZeneca vaccine (OR, 0.97; 95% CI, 0.82-1.15; I2= 0%). Bell palsy was significantly more common after SARS-CoV-2 infection (n = 2822072) than after SARS-CoV-2 vaccinations (n = 37912410) (relative risk, 3.23; 95% CI, 1.57-6.62; I2= 95%). Conclusions and Relevance: This systematic review and meta-analysis suggests a higher incidence of BP among SARS-CoV-2-vaccinated vs placebo groups. The occurrence of BP did not differ significantly between recipients of the Pfizer/BioNTech vs Oxford/AstraZeneca vaccines. SARS-CoV-2 infection posed a significantly greater risk for BP than SARS-CoV-2 vaccination.