NEW research has identified Guillain-Barré Syndrome (GBS) as a potential adverse event following the ChAdOx1-S/nCoV-19 COVID-19 vaccine.
In April 2021, an analysis was conducted in three districts of Kerala, India, where approximately 1.5 million individuals had been vaccinated against COVID-19. The majority (1.2 million people, over 80%) received the ChAdOx1-S/nCoV-19 vaccine. Within a four-week period from mid-March to mid-April 2021, seven cases of GBS were observed within two weeks of receiving the first dose of this vaccine. These cases presented with severe symptoms, including bilateral facial weakness—a feature noted in less than 20% of typical GBS cases—highlighting an unusual pattern potentially associated with the vaccine.
The observed incidence of GBS was markedly higher than expected for a population of this size, with an increase ranging from 1.4- to 10-fold compared to baseline rates. The estimated frequency was approximately 5.8 cases per million doses administered. Notably, six of the seven patients progressed to areflexic quadriplegia and required mechanical ventilatory support. This finding underscores the seriousness of the cases and suggests a need for heightened awareness among clinicians regarding post-vaccination neurological symptoms, even as the overall risk remains low.
The findings suggest a rare but serious adverse event linked to the ChAdOx1-S/nCoV-19 vaccine. Nevertheless, the benefits of COVID-19 vaccination far outweigh the risks, particularly in regions with high disease transmission. Clinicians are advised to remain vigilant for early signs of GBS in recently vaccinated individuals to ensure timely intervention, which is critical for patient outcomes. Future studies should investigate the underlying mechanisms of this association and whether certain populations are at increased risk. Public health strategies must balance the ongoing need for widespread vaccination with continued monitoring and transparent reporting of rare adverse events to maintain public trust.
Katrina Thornber, EMJ
Reference
Maramattom BV et al. Guillain-Barré Syndrome following ChAdOx1-S/nCoV-19 vaccine. Ann Neurol. 2021;90(2):312-314.
