A study from Japan is causing a stir. The research team examined brain tissue and brain arteries of patients who had suffered a haemorrhagic stroke. In 43.8% of vaccinated patients, the SARS-CoV-2 spike protein was detected in the innermost layer of the brain arteries, even 17 months after vaccination. None of these patients had an active COVID-19 infection. The researchers were able to confirm that the presence of the spike protein with mRNA vaccines was not associated with a previous viral infection.