Warning about possible risk of Guillain-Barré syndrome with viral vector covid-19 vaccines


Recommendations of the COVID-19 Subcommittee of WHO's Global Advisory Committee on Vaccine Safety (GACVS)

On 13 and 20 July 2021, the COVID-19 subcommittee of the WHO Global Advisory Committee on Vaccine Safety (GACVS) met virtually to discuss rare reports of Guillain-Barré Syndrome (GBS) following vaccination with the Janssen and AstraZeneca COVID-19 vaccines, and to consider measures implemented by the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA).

The subcommittee also reviewed preliminary data from Vigibase, the WHO global database of Individual Case Safety Reports (ICSR), which listed 164 unconfirmed cases of GBS in various countries (other than the United States) associated with the AstraZeneca (Vaxzevria and Covishield) vaccines. Fourteen of these cases were in Central and South American countries, out of a total of 19.5 million doses of AstraZeneca (Vaxzevria and Covishield) vaccines administered. 

Based on a careful scientific review of the available information, the GACVS subcommittee came to the following conclusions and recommendations:

  • Rare cases of GBS have been reported following vaccinations with adenovirus vector COVID-19 vaccines.
  • Increased reports of GBS have not been observed following mRNA COVID-19 vaccines.
  • More rigorous studies using alternative data sources and robust study designs, and comparison of vaccinated and unvaccinated populations would be needed, to fully assess the significance of these events. 
  • The GACVS subcommittee will continue to monitor GBS and any other safety concerns and review further as more data become available.
  • Healthcare professionals should monitor for and report all adverse events including GBS. 
  • Individuals receiving Janssen or AstraZeneca COVID-19 vaccines should be alert to signs and symptoms of GBS and should seek immediate medical attention if they develop weakness/tingling and paralysis in the extremities that may progress to other parts of the body including the chest and face. Symptoms may include difficulty in walking; difficulty with facial movements; double vision or inability to move eyes; or difficulty controlling bladder or bowel functions.
  • Healthcare professionals should be aware of these signs and symptoms to allow for early diagnosis and treatment. Most people fully recover from GBS.
  • Though countries should always consider their individual circumstances and benefit-risk profiles, overall the subcommittee concludes that the potential benefits of both the Janssen and AstraZeneca 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.


Source: https://www.who.int/news/item/26-07-2021-statement-of-the-who-gacvs-covid-19-subcommittee-on-gbs   


European Medicines Agency on Janssen's COVID-19 vaccine

On 22 July 2021, the European Medicines Agency (EMA) reported that Guillain-Barré Syndrome (GBS) will be listed as a very rare side effect of Janssen's COVID-19 vaccine. The vaccine information will be updated to include, in the section on warnings and special precautions for use, that very rare cases of GBS have been reported following administration of the Janssen COVID-19 vaccine.

Health professionals should be alert to signs and symptoms of GBS to ensure correct diagnosis, to initiate adequate supportive care and treatment, and to rule out other causes. Vaccinated individuals should be advised to seek immediate medical attention if they develop signs and symptoms of GBS (such as those mentioned in the previous section). 

Source: https://www.ema.europa.eu/en/news/covid-19-vaccine-janssen-guillain-barre-syndrome-listed-very-rare-sideeffect


A similar measure was announced on 19 July 2021, by the EMA, for AstraZeneca's Vaxzevria COVID-19 vaccine.

Additional information on this measure is available at:


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