There have been very rare reports of cases of Guillain-Barré syndrome occurring within 42 days of vaccination with the AstraZeneca and Janssen vaccines (adenovirus vector vaccines). Guillain-Barré syndrome is a rare condition in which a person’s immune system attacks the nerves, causing muscle weakness, tingling and/or loss of sensation in the arms and/or legs. Most people affected recover fully. Although these cases happened after vaccination, it is not yet possible to tell whether they were related to or caused by the vaccines or if they were coincidental. The benefits of vaccination against COVID-19 greatly outweigh any possible risk.
Globally, vaccines such as AstraZeneca and Johnson &Johnson/Janssen have been used to protect millions of people against COVID-19. Data are available from both clinical trials and preliminary data from country surveillance programmes on their efficacy and safety. Some mild to moderate side effects such as fever, muscle and headaches, soreness around the injection site and tiredness are expected to affect some people after vaccination. These are a normal indication that the body is developing protection.
As of the 27 June 2021, the European Medicines Agency had received reports of 227 cases of Guillain-Barré syndrome in the European Union following vaccination with AstraZeneca. Around 51.4 million doses of Vaxzevria (the brand of AstraZeneca produced in Europe) had been administered within the European Union by 20 June 2021. For the Janssen vaccine, the US Advisory Committee on Immunization Practices reported that 100 cases of Guillain-Barré syndrome had been reported through the Vaccine Adverse Events Reporting System in the United States of America (USA) as of 30 June 2021, with approximately 12.2 million doses of the Janssen vaccine administered. Outside of the European Union and the USA, cases of Guillain-Barré syndrome have also been reported; however, further investigation is needed to determine whether the rate has increased from usual levels.
Guillain-Barré syndrome has many causes, such as bacterial or viral infections, surgery or vaccine administration. It can also be caused by COVID-19. In 2011, it was estimated that the incidence of Guillain-Barré syndrome in Europe and Northern America was 0.8 to 1.9 cases out of every 100 000 people. It can affect people of all ages but is more common in adults and in males. Most people recover fully even from the most severe cases of Guillain-Barré syndrome; however, it is potentially life-threatening, and some people affected may need intensive care.
If you experience any of the following symptoms within 42 days of vaccination, contact your healthcare provider immediately:
- difficulty walking
- difficulty with facial movements, including breathing, speaking, chewing or swallowing
- double vision or being unable to move your eyes
- difficulty with bladder or bowel control
- weakness or tingling sensations in the legs, arms and face.
The benefits of the COVID-19 Janssen and AstraZeneca vaccines are far greater than the very small risk of developing Guillain-Barré syndrome. COVID-19 disease can also cause Guillain-Barré syndrome. WHO recommends that these vaccines continue to be used.
For more information, read the Statement of the COVID-19 subcommittee of the WHO Global Advisory Committee on Vaccine Safety (GACVS) COVID-19 subcommittee on reports of Guillain-Barré.
