How the coronavirus gets to the brain

The coronavirus can also attack the brain and cause neurological deficits such as olfactory disorders to strokes cause. Researchers at the Charité have found a possible explanation for this.

It has long been known that many Covid 19 patients suffer from neurological symptoms such as loss of smell and taste. In addition to these often long-lasting complaints, a corona infection can apparently also have more serious consequences.

According to the German Society for Neurology (DGN) “diffuse brain damage with neurological and psychiatric abnormalities, inflammation of the brain and spinal cord or strokes can occur”.

The curious thing is not only that Covid-19-Patients with cardiovascular risks stroke would suffer. A stroke can also occur in young, “vascularly healthy” people.

Study: Large majority not free of symptoms after Covid-19

The realization that neurological symptoms often persist longer is also worrying. This was shown by a study from Italy, which was published in July in the English-language journal “JAMA”. She examined whether and which complaints persisted in Covid 19 patients after discharge from the hospital. 87 percent of the sick showed symptoms afterwards.

According to this study, the most common neurological consequences were

• Tiredness or fatigue, i.e. persistent severe exhaustion (around 53 percent),
• Impairment of the sense of smell (about 16 percent),
• Taste disorders (about 11 percent),
• Headache (about ten percent),
• Dizziness (about five percent).

Headache: After a Covid-19 illness, some patients complain of persistent pain. (Source: NickyLloyd / Getty Images)

Study by the Berlin Charité: How SARS-CoV-2 gets into the brain

How exactly the coronavirus can penetrate the brain has long been unclear. Experts in neuropathology, pathology, forensic medicine, virology and clinical care at the Berlin Charité have now published new findings in the specialist magazine “Nature Neuroscience”.

Accordingly, the coronavirus reaches the brain via the nerve cells of the olfactory mucosa directly from the nose. The olfactory mucosa is located in the upper turbinates, on the so-called roof of the nose on both sides of the upper nasal septum. There are around ten million olfactory cells on it, as the German Professional Association of Otorhinolaryngologists explains.

The research team around Prof. Dr. Frank Heppner, Director of Neuropathology at Charité, examined 33 tissue samples from people who had died in connection with Covid 19 disease – on average at an age of almost 72 years. Using state-of-the-art methods, the scientists analyzed samples from the olfactory mucosa and four different brain regions.

The result: They were able to detect intact virus particles in various structures that connect the eyes, mouth and nose with the brain stem. The highest viral load was found in the olfactory mucosa. “On the basis of this data we assume that SARS-CoV-2 can use the olfactory mucous membrane as a portal of entry into the brain, “according to a statement. At the same time, according to the researchers, this explains the frequent disorders of the sense of smell and taste in corona infections.

How does corona spread from nerve cells?

However, the researchers point out that the study only examined deceased Covid 19 patients who suffered a severe course during their lifetime. It cannot be transferred to medium or light courses.

It is also still unclear how exactly the virus spreads from the nerve cells. The research team assumes that it migrates “from nerve cell to nerve cell” in order to reach the brain. However, transport via the blood vessel system is also possible, as data from the study show. Similarly spread also Herpessimplex virus or the rabies virus that causes rabies.

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