A study of the association between seasonal influenza vaccines and the increased risk of Guillain-Barré syndrome using Vaccine Adverse Event Reporting System, 2018-2019.

The aim of this study was to investigate the association between the incidence of Guillain-Barré syndrome (GBS) and seasonal influenza vaccines using the United States Vaccine Adverse Event Reporting System. Using multiple logistic regression analysis, we calculated the adjusted reporting odds ratio (ROR) of GBS cases associated with seasonal influenza vaccines administered from August 2018 to July 2019. Additionally, we analyzed the time-to-onset profile. The total number of adverse events reported following vaccination during this period was 43,235. Most of the GBS patients received a cell culture-based quadrivalent inactivated influenza vaccine (42.2%), quadrivalent inactivated influenza vaccine (26.6%), or high-dose trivalent inactivated influenza vaccine (15.6%). The adjusted ROR of seasonal influenza vaccines for GBS was 3.44 (2.40-4.95). The adjusted ROR of sex (male) (as reference female) and 0.5-59 years (as reference ≥ 60 years) were 1.90 (0.73-4.95) and 1.57 (0.88-2.78). Male sex and advanced age were not risk factors for GBS. The median duration of GBS was 9.5 (4.0-21.5) days. GBS following seasonal influenza vaccination developed mainly within 14 days and 42 days at most. In sex-stratified analyses, the median durations of GBS in females and males were 12.0 (8.3-28.5) and 5.0 (3.0-15.5) days ( = 0.050). Therefore, our findings indicate that the incidence of GBS is associated with seasonal influenza vaccines, and careful monitoring of GBS is required for up to 42 days, especially in the first 14 days. Moreover, GBS may occur slightly earlier in males than in females.