evidence: There is no evidence the swab used to test for COVID-19 could compromise the blood-brain barrier. [...] It is simply not possible for the nasopharyngeal swabs used in COVID-19 tests to compromise the blood-brain barrier. [...] It would not be possible for the 6-inch nasopharyngeal swabs used in COVID-19 tests to compromise the blood-brain barrier, which refers to the tightly packed cells inside the blood vessels of the brain.