One of the ongoing discussions regarding the Coronavirus aims to understand the reason behind the neurological symptoms of COVID-19. Since the pandemic emerged in late 2019, the virus has been known for its novel effects on the brain, such as severe fatigue, cognitive distortions, loss of smell and taste, and brain fog. Scientific studies are attempting to determine precisely how COVID-19 causes these symptoms.
In this context, two hypotheses have emerged. One school of thought suggests that these neurological issues stem from the virus directly infiltrating the brain and damaging its cells. In this process, nerve cells are destroyed, and the body's inflammatory response leads to further damage, according to New Atlas citing the journal Nature Neuroscience. The other hypothesis posits that secondary systemic inflammation is the source of these neurological symptoms. The virus does not directly damage the brain; rather, the body's exaggerated immune response due to the infection causes the problems.
Since then, evidence supporting both ideas has appeared. For example, studies conducted on animals and cells have clearly shown that the virus can theoretically infect brain cells. Naturally, proving this in humans is nearly impossible because, practically, living brains cannot be placed under a microscope. Thus, autopsy investigations mostly rely on looking for faint traces of the virus in tissue samples.
Some studies have succeeded in detecting markers of the virus in the brain, but the results have not been sufficient to conclude that COVID-19 actually infects nerve cells. So far, the inflammation hypothesis has been slightly more convincing. Four years after the onset of the COVID pandemic, it has become clear that the virus is harmful to the brain, and many studies have effectively indicated significant signs of inflammatory damage. However, questions have again arisen about what causes the inflammatory damage.
A new study conducted by a team of European researchers led by scientists at Charité, a medical school affiliated with Humboldt University and the Free University of Berlin, sought to address the mystery of the impact of the Coronavirus on the brain by starting from scratch. They first closely examined brain tissue samples from 21 individuals who died due to severe Coronavirus infection. As with previous studies, traces of the Coronavirus were found in brain tissue samples, but importantly, the researchers were unable to detect any signs of direct neuronal infection.
