"43 patients were included in our study. Patients died in hospitals, nursing homes, or at home, and were aged between 51 years and 94 years (median 76 years [IQR 70-86]). We detected fresh territorial ischaemic lesions in six (14%) patients. 37 (86%) patients had astrogliosis in all assessed regions. Activation of microglia and infiltration by cytotoxic T lymphocytes was most pronounced in the brainstem and cerebellum, and meningeal cytotoxic T lymphocyte infiltration was seen in 34 (79%) patients. SARS-CoV-2 could be detected in the brains of 21 (53%) of 40 examined patients, with SARS-CoV-2 viral proteins found in cranial nerves originating from the lower brainstem and in isolated cells of the brainstem."
https://pubmed.ncbi.nlm.nih.gov/33031735/
It's astounding how seemingly most people just jump to "oh its in your head, just some anxiety". A fairly nasty virus, that causes severe disease that literally kills people even. Penetrates into the brain, cranial nerves, spinal fluid. Causes peripheral neuropathies, palsies, paralysis.
..but no, let's just ignore all that and jump straight to "it's all in your head"
the original covid is conclusively known to impair your sense of smell, sometimes total anosmia. Sometimes total anosmia for life, but luckily that seems rare.
Blood brain barrier? The olfactory bulb in your nose does NOT have the blood brain barrier. But you didn't know that, did you? Remember this next time when you are going swimming.
Never been infected? That would require lymphocyte testing, and none of those tests have been clinically validated, and never will be. no money in that, and original strains no longer circulate.
Do you have any biology training aside from mandatory high school curriculum?