Quality of and methodological heterogeneity in COVID-19 vaccine safety studies - Case study of Bell's palsy safety signal

Abstract

In this systematic review, the methodological quality of published observational studies evaluating risk of Bell’s palsy following COVID-19 vaccination was assessed, the heterogeneity across studies addressing similar questions was characterized, and finally, the sources of heterogeneity, focussing on the impact of study design specification, was investigated.