SARS-CoV-2 vaccine-related neurological complications

Objective To describe three cases with neurological symptoms after SARS-CoV-2 vaccination. Methods A case series followed by a review of the literature, describing hypotheses on how neurological symptoms might develop after vaccination. Results The different temporal relationship between the onset or worsening of different neurological symptoms suggests different pathophysiological mechanisms. Progression of post-infectious myoclonus, caused by a previous SARS-CoV-2-infection, shortly after vaccination suggests a renewed auto-immune mediated crossreaction of antibodies to both viral epitopes and central nervous system components. Thunderclap headache after vaccination suggests a similar pathophysiological mechanism to the headache and other flu-like symptoms described after vaccination against other viruses. This might be ascribed to the activation of immunoinflammatory mediators or accompanying fever. Although headache accompanied by encephalopathy and focal neurological deficit might occur as part of a cytokine release syndrome, this is clinically less likely. Conclusions A variety of symptoms, including thunderclap headache, focal deficits and movement disorders, can occur after SARS-CoV-2 vaccination, and an activation or reactivation of the immune system is suggested as most likely cause. However, one should be careful about claiming a direct correlation. It remains important to exclude other causes, such as structural lesions, infections or subarachnoid hemorrhage, and future research is required to understand possible pathophysiological mechanisms and associations with the SARS-CoV-2 vaccine.

Automated summary

This study describes three cases of neurological symptoms after SARS-CoV-2 vaccination and proposes possible pathophysiological mechanisms. Thunderclap headache may be related to the activation of immunoinflammatory mediators or fever, while the progression of post-infectious myoclonus may be associated with auto-immune mediated crossreaction. Further research is needed to understand the pathophysiological mechanisms of the SARS-CoV-2 vaccine and its association with neurological symptoms.