Risk of Guillain-Barré syndrome after human papillomavirus vaccination

Boender T Sonia, Bart Meyer Barbara, Cool Louise, Wichman Ore, Difficult Thomas. Risk of Guillain-Barré syndrome after vaccination against human papillomavirus: a systematic review and meta-analysis, January 1, 2000 to April 4, 2020. Euro Surveillance. 2022; 27(4): pii = 2001619. https://doi.org/10.2807/1560-7917.ES.2022.27.4.2001619

Commentary

Guillain-Barre syndrome (GBS) is an autoimmune disease following viral infection and is recognized as a rare mono. It has been reported that some of these cases are associated with vaccination.

According to pre-licensing clinical trials, no association between human papillomavirus (HPV) vaccination and GBS has been observed; a 2017 post-marketing surveillance reported an increased relative risk.

This study assessed the risk of GBS after HPV vaccination through a systematic literature review and meta-analysis.

We searched Embase, MEDLINE, and Cochrane for studies reporting the risk of GBS after HPV vaccination in individuals aged 9 years and older published between January 1, 2000, and April 4, 2020. Seven studies reporting relative effect sizes were pooled using a random-effects meta-analysis and the quality of the evidence was assessed using the GRADE approach.

The results included 25 studies out of 602 identified records; based on over 10 million reports, cases of GBS are rare; 22 studies did not observe an increased risk, while 3 studies reported an increased risk of GBS after HPV vaccination. In 22 studies, no increased risk was observed, but three studies found signs of increased risk of GBS after HPV vaccination.

A meta-analysis from these yielded a pooled random effect ratio of 1.21 (95% CI: 0.60-2.43) I 2 = 72% (95% CI: 36-88). This is equivalent to the number of people needed to harm 1 million people to be vaccinated in order to generate one GBS case, according to the study. The quality of this evidence is very low, they said.