Risk of Guillain-Barre syndrome after COVID-19 vaccination or SARS-CoV-2 infection: A multinational self-controlled case series study

Background: The association between Guillain-Barré syndrome (GBS) and certain COVID-19 vaccines is inconclusive. We investigated the risk of GBS after COVID-19 vaccination or SARS-CoV-2 infection. Methods: Using a common protocol, we conducted a self-controlled case series study from 1 December 2020 to 9 August 2023 at 20 global sites within the Global Vaccine Data Network (GVDN). Brighton Collaboration case definition criteria were used to determine the level of certainty (LOC) of medical record-reviewed GBS cases at 15 sites. GBS cases following SARS-CoV-2 infection were identified from electronic data sources (EDS) from 11 sites. We estimated the relative incidence (RI) of GBS within 1-42 days following receipt of adenoviral vector, mRNA, or inactivated COVID-19 vaccines or SARS-CoV-2 infection using conditional Poisson regression models, controlling for seasonality. We used random effects meta-analysis to pool the estimates across sites. Results: Of 410 medical record-reviewed post-vaccination GBS cases (out of 2086 EDS-identified cases), 49 were LOC 1 or 2, 187 were LOC 3 or 4, and 174 were LOC 5. These cases received a total of 794 doses of COVID-19 vaccines (160 20 % adenoviral vector vaccine doses, 556 70 % mRNA vaccine doses, 77 10 % inactivated vaccine doses, and 1 0.1 % protein-based vaccine dose) during the observation period. We observed an increased risk of confirmed (LOC 1-2) GBS after receiving ChAdOx1-S/nCoV-19 (Vaxzevria/Covishield) (RI = 3.10; 95 % confidence interval CI, 1.12-8.62). Decreased risks of LOC 1-4 GBS were observed after receiving BNT162b2 (Comirnaty/Tozinameran) (RI = 0.48; 95 %CI, 0.27-0.85) and CoronaVac/Sinovac (RI = 0.04; 95 %CI, 0.00-0.61). For 489 EDS-identified GBS cases after SARS-CoV-2 infection, we found GBS risk to be increased (RI = 3.35; 95 %CI, 1.83-6.11). Conclusion: In this large multinational study, we found increased risks of GBS within 42 days after Vaxzevria/Covishield vaccination or SARS-CoV-2 infection, and decreased risks after receiving Comirnaty/Tozinameran or CoronaVac/Sinovac COVID-19 vaccines.