the staff of the Ridgewood blog
Washington DC, the US FDA announced that it is including a warning regarding the risk of Guillain-Barré syndrome (GBS), a rare but potentially serious autoimmune neurological condition, associated with the J&J-Janssen SARS-CoV-2 vaccine. To date, there have been approximately 100 preliminary reports of GBS among 12.8 million recipients of the J&J-Janssen vaccine, but additional data are required in order to establish a causal relationship. Most of the cases have been identified within 2 weeks of vaccination, and mostly among men aged 50 years and older. Regulatory officials have not identified a similar trend associated with the Pfizer-BioNTech or Moderna vaccines. However, the FDA’s update comes only days after the European Medicines Agency’s Pharmacovigilance Risk Assessment Committee recommended including a warning to raise awareness among healthcare professionals and people taking the AstraZeneca-Oxford vaccine of GBS cases reported following vaccination. Both the J&J-Janssen and AstraZeneca-Oxford vaccines are adenovirus vector vaccines.
While rare in terms of the frequency of cases, GBS is a known risk associated with viral infections and other vaccines. The FDA includes warnings regarding GBS risk for several common vaccines, including both the nasal mist and injection versions of the seasonal influenza vaccine and the DTaP (diphtheria, tetanus, and pertussis) vaccine. Prior research has also found elevated risk of GBS following seasonal influenza infections, which is orders of magnitude higher than from the vaccine.
On average, approximately 3,000-6,000 cases of GBS are reported annually in the US. One previous COVID-19 study involving more than 70,000 COVID-19 patients in Spain estimated the GBS risk following infection to be 0.15%, which is approximately 1,500 GBS cases per million SARS-CoV-2 infections. One previous study on GBS and seasonal influenza found the GBS risk to be approximately 1 case per million seasonal influenza vaccinations and 18 cases per million cases of seasonal influenza. Like with other adverse events identified following SARS-CoV-2 vaccination, experts emphasize that the benefits far outweigh the risks.