PCR test

This is the test for SARS-CoV-2 which involves a nasal swab.  The test aims to detect the presence of virus RNA.  PCR stands for polymerase chain reaction.  Some people find it uncomfortable but it is not dangerous.

 However, to understand the latest myth that has sprung up about the danger of the test we need to know about the blood-brain barrier.  This is a semi-permeable membrane between the blood supply to the brain and the brain itself, which filters out various undesirable things and selectively allows in nutrients for neural cells. Among the things filtered out are pathogens, meaning that blood-borne infections of the brain are extremely rare.  The rumour has spread through social media that the swab reaches the blood-brain barrier and could break the delicate membrane, causing all sorts of diseases to enter the brain. Indeed the people pushing this rumour are hinting that this is the only reason that the authorities are asking for so many people to be tested, even those who show no symptoms. Presumably they want to kill us with brain diseases.

 This of course is not true. The swab is aiming for the area between the back of the nose and the throat.  To get to the blood-brain barrier it would have to push its way through bone at the base of the skull, which is not possible. The rumour has been debunked but that doesn’t stop some people from believing it.