Veria - Claim Fact Check

Claim: COVID‑19 vaccination disrupts the blood‑brain barrier, allowing vaccine material or spike proteins to enter the brain.

The claim conflates findings from SARS-CoV-2 infection with those from vaccination. Studies showing spike protein crossing or disrupting the blood-brain barrier were conducted with the virus or purified spike protein, not with COVID-19 vaccines ¹².
The lead author of the widely cited mouse study on S1 protein crossing the blood-brain barrier (Rhea et al., Nature Neuroscience) explicitly stated the work examined the virus, not the vaccine, and experts note doctored images misrepresent it on social media ¹.
The Associated Press fact-checked a related German study and confirmed it investigated spike protein accumulation from COVID-19 infection; the authors stated they performed “zero experiments using vaccine” and claim “zero side effects of the vaccine” ³.
The FDA and CDC state there is no evidence that vaccine-generated spike protein is toxic or lingers at harmful levels in the body, and multiple experts say the spike protein produced by vaccines is not pathogenic ⁴.
Animal biodistribution studies detected trace levels of mRNA/LNP in the brain (~2–4% of plasma levels in mice), but these did not use commercial products and do not demonstrate BBB disruption by vaccination ⁵.
Vaccine safety reviews indicate severe neurological adverse events are extremely rare (about 1 case per million doses) and that evidence for BBB disruption mechanisms comes from viral studies, not vaccine studies ².
General vaccine science holds that vaccines do not damage the blood-brain barrier; the barrier normally excludes proteins and vaccine components unless infection-related damage occurs ⁶.

Overall validity: 5%