| Meta-analysis Systematic Review  

Guillain-Barré syndrome and COVID-19 vaccination: a systematic review and meta-analysis

Case-reports/series and cohorts of Guillain-Barré syndrome (GBS) associated with COVID-19 vaccination have been reported. In this article, a systematic review and meta-analysis of cohort studies of GBS after COVID-19 vaccination was carried out. Incidence and incidence rate ratio for a number of vaccine doses and risk of GBS, also considering the specific vaccine technology, were calculated in a random-effects model. Of 554 citations retrieved, 518 were discarded as irrelevant. 15 studies were finally included. The random effect model yielded, regardless of the vaccine technology, 1.25 (95%CI 0.21; 2.83) GBS cases per million of COVID-19 vaccine doses, 3.93 (2.54; 5.54) cases per million doses for adenovirus-vectored vaccines and 0.69 (0.38; 1.06) cases per million doses for mRNA vaccines. The GBS risk was 2.6 times increased with the first dose. Regardless of the vaccine technology, the GBS risk was not increased but disaggregating the data it was 2.37 (1.67; 3.36) times increased for adenovirus-vectored vaccines and 0.32 (0.23; 0.47) for mRNA vaccines. Mortality for GBS after vaccination was 0.10 per million doses and 4.6 per GBS cases. The authors concluded that adenovirus-vectored vaccines showed a 2.4 times increased risk of GBS that was about seven times higher compared with mRNA-based vaccines. The decreased GBS risk associated with mRNA vaccines was possibly due to an elicited reduction of infections, including SARS-CoV-2, associated with GBS during the vaccination period. How adenovirus-vectored COVID-19 vaccines may trigger GBS is unclear and further studies should investigate the relationship between vaccine technologies and GBS risk.

Censi S, Bisaccia G, Gallina S, Tomassini V, Uncini A. Guillain-Barré syndrome and COVID-19 vaccination: a systematic review and meta-analysis. J Neurol. 2024 Jan 17. doi: 10.1007/s00415-024-12186-7.