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Is There an Increased Risk for Guillain-Barré Syndrome After COVID-19 Vaccination?

  • Authors: News Author: Megan Brooks; CME Author: Charles P. Vega, MD
  • CME / ABIM MOC / CE Released: 6/6/2022
  • Valid for credit through: 6/6/2023
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Target Audience and Goal Statement

This activity is intended for physicians, nurses, pharmacists, physician assistants, and all other members of the healthcare team who advise patients regarding COVID-19 vaccination.

The goal of this activity is for learners to be better able to analyze the risk for Guillain-Barré syndrome (GBS) after COVID-19 vaccination.

Upon completion of this activity, participants will:

  • Assess the risk for GBS associated with application of the influenza vaccine
  • Analyze the risk for GBS after COVID-19 vaccination
  • Outline implications for the healthcare team


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News Author

  • Megan Brooks

    Freelance writer, Medscape


    Disclosure: Megan Brooks has disclosed no relevant financial relationships.

CME Author

  • Charles P. Vega, MD, FAAFP

    Health Sciences Clinical Professor of Family Medicine
    University of California, Irvine School of Medicine


    Disclosure: Charles P. Vega, MD, has disclosed the following relevant financial relationships:
    Served as an advisor or consultant for: GlaxoSmithKline; Johnson & Johnson Pharmaceutical Research & Development, L.L.C.

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  • Leigh A. Schmidt, MSN, RN, CMSRN, CNE, CHCP

    Associate Director, Accreditation and Compliance
    Medscape, LLC


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    Associate Director, Accreditation and Compliance
    Medscape, LLC


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  • Esther Nyarko, PharmD

    Director, Accreditation and Compliance
    Medscape, LLC


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Is There an Increased Risk for Guillain-Barré Syndrome After COVID-19 Vaccination?

Authors: News Author: Megan Brooks; CME Author: Charles P. Vega, MDFaculty and Disclosures

CME / ABIM MOC / CE Released: 6/6/2022

Valid for credit through: 6/6/2023


Note: The information on the coronavirus outbreak is continually evolving. The content within this activity serves as a historical reference to the information that was available at the time of this publication. We continue to add to the collection of activities on this subject as new information becomes available. It is the policy of Medscape Education to avoid the mention of brand names or specific manufacturers in accredited educational activities. However, manufacturer names related to COVID-19 vaccines may be provided in this activity to promote clarity. The use of manufacturer names should not be viewed as an endorsement by Medscape of any specific product or manufacturer.

Clinical Context

Guillain-Barré syndrome (GBS) is a rare but serious complication of vaccinations, and it is most often linked to the influenza vaccine. The risk for GBS was most closely associated with the influenza vaccine during the 1976 "swine flu" outbreak. In that year, more than 45 million people received influenza vaccinations over a short period, and there were almost 500 cases of GBS related to vaccination.[1]

A meta-analysis by Martín Arias and colleagues assessed the overall risk for GBS associated with the influenza vaccine, and their results were published in the July 17, 2015 issue of Vaccine.[2] Overall, the relative risk for GBS associated with influenza vaccination was 1.41 (95% CI: 1.2, 1.66). The risk was particularly increased with pandemic influenza vaccines; the risk for GBS associated with seasonal influenza vaccine was marginally significant. The use of adjuvanted pandemic vaccines did not significantly increase the risk for GBS.

Of course, the risk for GBS is also increased after infection with influenza, so only a history of GBS related to the influenza vaccine is an absolute contraindication to vaccination. Guillain-Barré syndrome has also been reported after application of the COVID-19 vaccines. The current study by Hanson and colleagues analyzes the association, if any, between COVID-19 vaccination and the risk for GBS.

Study Synopsis and Perspective

New surveillance data from the Vaccine Safety Datalink confirm a small but statistically significant increased risk for GBS in the 3 weeks after receipt of the Johnson & Johnson/Janssen COVID-19 vaccine.

The Janssen vaccine (Ad.26.COV2.S) is a replication-incompetent adenoviral vector vaccine.

The data show no increased risk for GBS with the Pfizer (BNT162b2) or Moderna (mRNA-1273) shots: both mRNA vaccines.

"Our findings support the current guidance from US health officials that preferentially recommend use of mRNA COVID-19 vaccines for primary and booster doses," Nicola Klein, MD, PhD, with Kaiser Permanente Vaccine Study Center, Oakland, California, told Medscape Medical News.

"Individuals who choose to receive Janssen/J&J COVID-19 vaccine should be informed of the potential safety risks, including GBS," Klein said.

The study was published online April 1 in JAMA Network Open.[2]

11 Cases

Between mid-December 2020 and mid-November 2021, approximately 15.1 million doses of COVID-19 vaccine were administered to nearly 7.9 million adults in the United States.

This includes roughly 483,000 doses of the Janssen vaccine, 8.8 million doses of the Pfizer vaccine, and 5.8 million doses of the Moderna vaccine.

The researchers confirmed 11 cases of GBS after the Janssen vaccine.

The unadjusted incidence of GBS (per 100,000 person-years [PY]) was 32.4 in the first 21 days after the Janssen vaccine: substantially higher than the expected background rate of 1 to 2 cases/100,000 PY.

There were 36 confirmed cases of GBS after mRNA vaccines. The unadjusted incidence in the first 21 days after mRNA vaccination was 1.3/100,000 PY, similar to the overall expected background rate.

In an adjusted head-to-head comparison, GBS incidence during the 21 days after receipt of the Janssen vaccine was 20.6 times higher than the GBS incidence during the 21 days after the Pfizer or Moderna mRNA vaccines, amounting to 15.5 excess cases/1 million Janssen vaccine recipients.

Most cases of GBS after the Janssen vaccine occurred during the 1- to 21-day risk interval, with the period of greatest risk in the 1 to 14 days after vaccination.

The findings of this analysis of surveillance data of COVID-19 vaccines are "consistent with an elevated risk of GBS after primary Ad.26.COV2.S vaccination," the authors wrote.

Novel Presentation?

The researchers noted that nearly all individuals who developed GBS after the Janssen vaccine had facial weakness or paralysis, in addition to weakness and decreased reflexes in the limbs, suggesting that the presentation of GBS after COVID-19 adenoviral vector vaccine may be novel.

"More research is needed to determine if the presentation of GBS after adenoviral vector vaccine differs from GBS after other exposures such as Campylobacter jejuni, and to investigate the mechanism for how adenoviral vector vaccines may cause GBS," Klein and colleagues said.

"The Vaccine Safety Datalink continues to conduct safety surveillance for all COVID-19 vaccines, including monitoring for GBS and other serious health outcomes after vaccination," Klein told Medscape Medical News.

This study was supported by the Centers for Disease Control and Prevention (CDC). Klein reported receiving grants from Pfizer Inc. research support for a COVID-19 vaccine clinical trial as well as other unrelated studies, grants from Merck & Co., Inc.; grants from GlaxoSmithKline, grants from Sanofi Pasteur, and grants from Protein Science (now Sanofi Pasteur) outside the submitted work.

Study Highlights

  • Investigators drew study data from the Vaccine Safety Datalink system, which contains data from 8 large US healthcare systems as well as the CDC.
  • The datalink has surveilled COVID-19 vaccine safety since December 2020, following 23 prespecified outcomes on a weekly basis. The current study evaluates rates of GBS in the period after vaccination with a COVID-19 vaccine compared with background GBS activity in the community and between the adenovirus-based Ad.26.COV2.S vaccine (Johnson and Johnson/Janssen) and the mRNA-based vaccines (Pfizer/BioNTech and Moderna).
  • The researchers identified cases of GBS via diagnostic codes and then adjudicated in the medical record. The current analysis contained data through November 13, 2021.
  • The researchers adjusted results based on demographic data.
  • The study analysis included a total of 15,120,073 COVID-19 vaccines among 7,894,989 individuals aged ≥ 12 years; 53.8% of study participants were female, and the mean age of the cohort was 46.5 ± .02 years. The cohort was diverse in terms of race/ethnicity.
  • There were 483,053 doses of Ad.26.COV2.S available for analysis, with nearly two-thirds of all of these vaccinations documented between February and April 2021: 96.8% of all vaccine doses were mRNA vaccines.
  • There were 11 confirmed cases of GBS from 1 to 84 days after receipt of the Ad.26.COVS.S vaccine: 9 of these cases developed symptoms from 1 to 21 days after vaccination.
  • The mean age of patients with GBS after Ad.26.COV2.S was 50 ± 12years, and 82% were male; 91% of these patients had facial weakness or paralysis in addition to bilateral limb symptoms. This high rate of facial weakness should be followed in future studies.
  • The unadjusted incidence rates of GBS were 32.4/100,000 PY during days 1 to 21 after vaccination with Ad.26.COV2.S and 18 cases/100,000 PY for the period 1 to 42 days after vaccination. These rates were significantly higher than the background rate in the general population.
  • The rate ratio of GBS in comparing days 1 to 21 and 22 to 42 after administration of Ad.26.COV.S was 6.03 (95% CI: 0.79, 147.79). The respective RR in comparing days 1 to 42 and 43 to 84 after vaccination was 8.64 (95% CI: 1.18, 207.32).
  • 36 cases of GBS were confirmed after application of the mRNA vaccines. There was a total of 1.3 cases of GBS/100,000 PY in the 21 days after mRNA vaccines, which was similar to the background rate of GBS. The relative risk (RR) for GBS associated with mRNA vaccines vs no vaccination was 0.83 (95% CI: 0.5, 1.33).
  • The RR for GBS in comparing Ad.26.COV2.S vs mRNA vaccines was 20.56 (95% CI: 6.94, 64.66). This absolute risk translated to 15.5 excess cases of GBS for each million persons receiving Ad.26.COV2.S instead of mRNA vaccines.

Clinical Implications

  • A previous meta-analysis by Martín Arias and colleagues found a significant increase in the risk for GBS associated with the influenza vaccine, particularly vaccines applied during influenza pandemics.
  • The current study by Hanson and colleagues finds a small but significant increase in the risk for GBS associated with Ad.26.COV2.S, but no such risk with mRNA vaccines.
  • Implications for the healthcare team: The healthcare team should be aware of a higher risk for GBS associated with Ad.26.COV2.S, although the absolute number of additional GBS cases associated with vaccination will be small.

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