- Would screening Covid-19 actually expose them to far more serious dangers?
- This is what claims a disturbing post posted on Facebook, claiming that the swabs inserted in the nose on this occasion can touch the blood-brain barrier protecting the brain.
- However, this is a set of claims without any scientific basis, as explained by a doctor and a neurovirology specialist at 20 Minutes.
Are you planning to do a PCR test to find out if you have coronavirus? While different Covid-19 screening practices are increasing in France, a Facebook post intends to dissuade you from such an initiative.
According to this particularly anxiety-provoking text, introduced by a shock formula (“Swabs = danger”), these virological examinations, carried out using a swab introduced into the nose or mouth, would actually present a serious danger for the health: “Your brain […] is protected from potentially harmful substances in the bloodstream by a fence-like structure called the blood-brain barrier. Why talk about it now, more than ever? Quite simply because the EXACT place where the “testers” (with the famous “long Q-Tip” test leading to the RT-PCR interpretation of the sample obtained) obtain your sample (for the “COVID-19” ) is called “blood-brain barrier”.
“Testers with their swabs – they take you in (really far) until you TOUCH the LAST PHYSICAL BARRIER before reaching your brain – put your blood-brain barrier IN DANGER”, continues the publication, before listing the innumerable risks that would be induced by such an attack on the blood-brain barrier: autism, stroke, cancer…
If these statements are enough to scare more than one Internet user, they are not based on any scientific basis. And they even make jump the specialists questioned on the subject.
“A swab does not come into contact with the barrier hematoencephalic, it would have to cross the mucous membrane and the bone of the skull to reach it! “Immediately recalls Daniel Dunia, director of research in neurovirology at the CNRS. “When we do a swab, we will look for secretions in the oropharyngeal sphere. “
Guillaume Martin-Blondel, doctor in the infectious diseases department of the Toulouse University Hospital, where thousands of tests of this kind have been carried out in recent months, abounds: “The aim is to recover secretions from the posterior nasopharyngeal wall , it is a technique used for a long time for different types of respiratory infection, it did not appear with the Covid-19. “
“This gesture, performed with a cotton swab-like swab, is not pleasant and it can eventually cause pain or bleeding of the mucous membrane in people with more fragile blood vessels, but it can in no case perforate the bone wall at the base of the skull is completely improbable, ”confirms the doctor.
A physical impossibility that can be seen in an explanatory video published by the New England Journal of Medicine (from 0’25 below). Especially since the possible cases of “compromise” of the barrier are very limited, and unrelated to this type of test, according to Daniel Dunia: “The only mechanical stress that could compromise the blood-brain barrier, it would be an epidural or a lumbar puncture. If the injection of the anesthetic into the vertebrae is improperly done, it can pierce the barrier. In this case, it causes severe but not fatal signs. “
“No meaning or scientific basis”
The Facebook post therefore evokes the very real existence of the blood-brain barrier but it then engages in a “demonstration” which completely disregards anatomical reality as common practices for screening for this type of virus.
If the depth at which the sample is inserted can surprise (or worry), it responds to a necessity, explained by Guillaume Martin-Blondel: “One of the limits of the test is that, if we stop at the nasal opening, we risk giving a falsely reassuring result. You really have to go to the posterior nasopharyngeal wall, stop there for a few seconds and then remove the sample by turning it to collect the secretions and be able to analyze the results. “
Finally, the so-called risks induced by an impairment of the blood-brain barrier (autism, stroke, etc.) are also part of an incredible scenario; lambasted by Daniel Dunia: “They are absolutely false, it is as if one said that autism circulates in the blood and that, as soon as a hole develops in the barrier, it develops. It has no meaning or scientific or real basis. “