evidence: Nasal swab used for COVID-19 testing does not reach the brain Nasal swabs are used to collect biological samples from the back of the nasopharynx in order to test for the presence of SARS-CoV-2 infection. The nasal swab has to be inserted far into the nasal cavity until it reaches the nasopharynx located behind it. The human brain is separated from the nasopharynx by several layers of hard tissue, including bone. It is therefore not possible for nasal swabs to reach the brain or the blood-brain barrier. [...] A Facebook post shared more than 16,000 times claims that the nasopharyngeal swab (nasal swab), which is widely used to collect biological samples for testing for active SARS-CoV-2 infection (the virus responsible for COVID-19), scrapes and damages the blood-brain barrier (BBB) leading to serious health problems. This claim is incorrect because it is anatomically impossible.