Reports of Guillain-Barré Syndrome following adenovirus vector COVID-19 vaccines

Advisory Alert

July 30, 2021

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To: Local Health System Partners


Rare reports of Guillain-Barré Syndrome following vaccination with adenovirus vector COVID-19 vaccines.

Guillain-Barré Syndrome (GBS) is a rare immune system disorder that results in muscle weakness, pain or numbness, and, in more severe cases, paralysis. GBS could result from different causes, including infections, and occurs more frequently in males and persons over 50 years old. Cases may occur coincidentally following vaccination.

Rare cases of GBS have been reported following vaccinations with adenovirus vector COVID-19 vaccines.

On July 26, the World Health Organization released a statement on increased reports of GBS following adenovirus vector vaccines reported from Europe, the United States, and abroad.

Current Canadian data from the Public Health Agency of Canada, reports a total of 48 cases of GBS following COVID-19 vaccination, 25 cases occurring among individuals who received COVISHIELD/AstraZeneca vaccines (0.91 reports per 100,000 doses administered).

Preliminary analysis shows the rate of GBS following COVISHIELD/AstraZeneca COVID-19 vaccination is higher than the rate of GBS following Pfizer-BioNTech or Moderna vaccination. As well, the number of cases of GBS following COVISHIELD/AstraZeneca vaccination are higher than would normally be expected in the general population.

Among the 25 reports of GBS following COVISHIELD/AstraZeneca vaccines:

Based on this information, please consider the following recommendations for your clinical practice:

The potential benefits of adenovirus viral vector COVID-19 vaccines continue to outweigh any potential risk of GBS, particularly given the increase in the more transmissible Delta (B.1.617.2) variant.

We will continue to share information on COVID-19 vaccine safety as it is received. Please contact the immunization program at 705.522.9200, ext. 458 or toll-free 1.866.522.9200 with any questions you may have.


Original Signed By

Dr. Penny Sutcliffe
Medical Officer of Health and Chief Executive Officer

NOTE: All Advisory Alerts are found on our website.

This item was last modified on July 30, 2021