Spike proteins that extrude from SARS-CoV-2 promote inflammatory responses on the endothelial cells that form the blood-brain barrier.
“For example, some people with COVID-19 experience headaches, nausea, vomiting, or "brain fog" – indicators of neurological involvement. Evidence from a 2020 study suggests that SARS-CoV-2, the virus that causes COVID-19, disrupts the blood-brain barrier.”