Cross-sectional case-control studies (Blue)
Read on for our pick of Covid-related cross-sectional case control studies from the scientific press for August 2022:
UK Covid Vaccine GBS Study Group. Guillain-Barré syndrome following SARS-CoV-2 vaccination in the UK: a prospective surveillance study
The aim of this study was to investigate features of Guillain-Barré syndrome (GBS) following SARS-CoV-2 vaccines and evaluate for a causal link between the two.
Cases of GBS after SARS-CoV-2 vaccination were captured through a national, open-access, online surveillance system. For each case, the certainty of GBS was graded using the Brighton criteria, and the relationship to the vaccine was examined using modified WHO Causality Assessment criteria. Age distribution of cases was compared with that of pre-pandemic GBS cases and clinical features with the International GBS Outcome Study (IGOS).
Between 1 January and 30 June 2021, the study team received 67 reports of GBS following the ChAdOx1 vaccine (65 first doses) and three reports following the BNT162b2 vaccine (all first doses). The causal association with the vaccine was classified as probable for 56 (80%, all ChAdOx1), possible for 12 (17%, 10 ChAdOx1) and unlikely for two (3%, 1 ChAdOx1). A greater proportion of cases occurred in the 50-59 age group in comparison with pre-pandemic GBS. The most common clinical variants were sensorimotor GBS (n=55; 79%) and facial diplegia with paresthesia (n=10; 14%). 10% (n=7/69) in patients who reported an antecedent infection, compared with 77% (n=502/652) of the IGOS cohort (p<0.00001). Facial weakness (63% (n=44/70) vs 36% (n=220/620); p<0.00001) and sensory dysfunction (93% (n=63/68) vs 69% (n=408/588); p=0.00005) were more common but disease severity and outcomes were similar to the IGOS study.
Most reports of GBS followed the first dose of ChAdOx1 vaccine. While this study does not confirm or refute causation, this observation, together with the absence of alternative aetiologies, different than expected age distribution and the presence of unusual clinical features support a causal link. The authors suggest that clinicians and surveillance bodies should remain vigilant to the possibility of this very rare adverse event and its atypical variants.
Tamborska AA, Singh B, Leonhard SE, Hodel EM, Stowe J, Watson-Fargie T, Fernandes PM, Themistocleous AC, Roelofs J, Brennan K, Morrice C, Michael BD, Jacobs BC, McDonald H, Solomon T; UK Covid Vaccine GBS Study Group. Guillain-Barré syndrome following SARS-CoV-2 vaccination in the UK: a prospective surveillance study. BMJ Neurol Open. 2022 Jul 12;4(2):e000309. doi: 10.1136/bmjno-2022-000309.