A link has been found between the first dosage of the AstraZeneca vaccination and a minor but significant increase in occurrences of the neurological illness Guillain-Barre syndrome (GBS).
According to University College London (UCL) researchers, the cause is yet unknown. They did highlight, however, that the limited number of GBS cases detected seemed to be comparable to increases previously documented in other mass immunisation campaigns.
In the study, published in the journal Brain, researchers observed that between January to October 2021, 996 GBS cases were recorded in the UK, but with an unusual spike in GBS reports occurring between March and April 2021.
“198 GBS cases occurred within 6 weeks of the first-dose COVID-19 vaccination in England (0.618 cases per 100,000 vaccinations, 176 ChAdOx1 nCoV-19 (AstraZeneca), 21 tozinameran (Pfizer), 1 mRNA-1273 (Moderna)). The 6-week excess of GBS (compared to the baseline rate of GBS cases 6-12 weeks after vaccination) occurs with a peak at 24 days post-vaccination; first-doses of ChAdOx1 nCoV-19 accounted for the excess. No excess was seen for second-dose vaccination.”
Lead author Professor Michael Lunn at UCL said “The reason for the association between only AstraZeneca vaccination and GBS is unclear. Covid-19 infection does not have a strong, or possibly any, increased risk of GBS, and the lack of increased risk associated with Pfizer vaccination implies that it is unlikely that the Covid-19 spike protein is the causative factor for the increased risk. The viral vector used to carry the nucleic acid in the AstraZeneca and similar vaccines may be the reason but this needs further exploration.”
