what is the incidence of Guillaume Barr syndrome after new shingles vaccine

The best estimate from a self-controlled case series is about 3 extra Guillain‑Barré cases per million doses of the new shingles vaccine (Shingrix), but the evidence is thin and the confidence interval includes zero.

The only study that directly estimates the risk comes from a self-controlled case series of people aged 65 and older, cited in a 2022 narrative review [2]. It found an attributable risk of 3.13 excess GBS cases per million doses within 42 days after vaccination, with a 95% confidence interval of 0.62 to 5.64 [2]. That means the true excess could be as low as 0.6 or as high as 5.6 per million doses. The lower end of that range is close to zero, so the signal is weak.

A separate 2026 descriptive analysis of VAERS reports counted 194 GBS reports among 69,822 herpes zoster vaccine reports (0.28%), with 168 of those linked to Shingrix [1]. But VAERS is a passive reporting system with no denominator of doses given, so this is a raw count, not a rate. Underreporting is the norm in such systems, meaning the true number of GBS cases could be higher, but the rate per dose cannot be calculated from these data alone [1].

The evidence base is narrow. The self-controlled case series is the strongest design here, but it was funded and run by the manufacturer's investigators, and the confidence interval includes a negligible risk. No long-term safety study comparing vaccinated to unvaccinated people was retrieved. The GBS risk appears small if it exists at all, but the data are not robust enough to call it zero.

My call: the risk of Guillain‑Barré syndrome after the new shingles vaccine is likely very low, around 3 per million doses, but the evidence is not strong enough to rule out a slightly higher or lower number. Confidence: low.