Can COVID-19 vaccination lead to neurological complications?

By Suchandrima BhowmikReviewed by Benedette Cuffari, M.Sc.Nov 14 2021

Most countries around the world have implemented widespread vaccination campaigns to protect their citizens against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although these vaccines are mostly well tolerated, they cause mild to moderate side effects in some patients. Recently, there have been anti-vaccine movements throughout the world, many of which are referring to the adverse effects of vaccines.

Study: Neurological side effects of SARS-CoV-2 vaccinations. Image Credit: Chaay_Tee / Shutterstock.com

Background

Normally, single case reports, case series, or registration studies report side effects, while systematic, transnational, multicenter, and post-marketing investigations are rarely done. This shortage of published information regarding vaccine side effects leads to resistance and reservations against vaccination in certain parts of a given nation’s population.

The neurological side effects reported due to SARS-CoV-2 vaccination are generally mild, self-limiting, of short duration, and manageable. However, in a few cases, these side effects were found to be severe and could require hospitalization or admission to intensive care units (ICU).

A new review article published in Acta Neurologica Scandinavica discussed published data to determine the type, frequency, treatment, and outcome of neurological side effects due to SARS-CoV-2 vaccination. The findings discussed in the current study also helped to determine whether certain patients were more prone to these adverse effects if they could be prevented, and which therapeutic management would be most appropriate.

About the study

The current study involved literature searches in PubMed and Google Scholar with search terms such as ‘vaccination,’ ‘anti-covid,’ ‘immunization,’ ‘side effects,’ ‘neurological,’ ‘adverse reactions,' ‘brain,’ and ‘nerves.’ The data were collected from December 2020 to September 2021.

Initially, 62 articles in PubMed and 4,580 articles in Google Scholar were found. However, most of the articles were rejected upon reading the title or abstract.

Only those articles that convincingly reported adverse neurological effects were included in the study. Additionally, the reference lists of the articles were also checked to determine whether any article matched the selection criteria. Finally, 28 articles were included in the current study.

Study findings

The collected literature indicated that the neurological side effects associated with SARS-CoV-2 vaccines included headache, transverse myelitis, Guillain-Barre Syndrome (GBS), facial nerve palsy, venous sinus thrombosis (VST), newly developing multiple sclerosis, and small fiber neuropathy. Among these effects, the most frequent adverse effect was headache followed by GBS, VST, and myelitis.

In most cases, headaches started within a few hours post-vaccination and resolved spontaneously after 48 hours. However, a subacute headache that occurs eight days post-vaccination and may be associated with VST has also been reported.

The onset of GBS post-vaccination might be due to molecular mimicry. SARS-CoV-2 vaccines induce immunization against the SARS-CoV-2 spike protein that binds to the sialic acid-containing glycoprotein and ganglioside on the surface of the cell. Therefore, antibody cross-reaction might be the causal link between GBS and SARS-CoV-2 immunization.

The third most frequent complication of SARS-CoV-2 vaccination is VST, which can cause hypercoagulability. The fourth most frequent complication is myelitis.

The current study also determined that neurological side effects can arise after the administration of any one of the available vaccines. However, myelitis predominantly developed after administration of the AstraZeneca vaccine (AZV).

Conclusion

Taken together, the current study discusses the side effects associated with SARS-CoV-2 vaccines that have been backed by various studies. Healthcare professionals, especially neurologists, should be aware of patients who have undergone SARS-CoV-2 vaccination. Further, these healthcare workers must be vigilant to recognize any early side effects and treat them immediately and efficiently.

The current study has one limitation that not all the patients having side effects were included in the study. Patients who had milder or non-detectable side effects were not included in the study.