A groundbreaking international study led by Yale University, the Brain Institute (Sorbonne University/Inserm/AP-HP/CNRS), and Pitié-Salpêtrière Hospital AP-HP provides definitive evidence that SARS-CoV-2—the virus behind the COVID-19 pandemic—can directly infect neurons. This discovery sheds light on neurological complications such as loss of smell, headaches, and strokes observed in many patients.
While COVID-19 is primarily known as a respiratory illness, extensive clinical data shows SARS-CoV-2 impacts multiple organ systems, including the central nervous system. Symptoms like headaches, anosmia (loss of smell), and cerebrovascular accidents (strokes) point to direct brain involvement, yet the underlying mechanisms have remained elusive—until now.
Published in the prestigious Journal of Experimental Medicine, the research employed three rigorous, independent methods to demonstrate SARS-CoV-2's ability to infect brain cells.
First, using advanced human brain organoids—miniature brains grown from stem cells in the lab—researchers observed clear viral infection, accompanied by metabolic disruptions in infected neurons and nearby cells.
Second, in mice genetically engineered to overexpress human ACE2 receptors (the protein SARS-CoV-2 uses to enter cells), the team confirmed neuroinvasion in a living model.
Third, autopsy analysis of deceased COVID-19 patients revealed SARS-CoV-2 in cortical neurons, along with associated damage like ischemic vascular events.
These converging lines of evidence establish the virus's neuroinvasive potential. As Inserm highlights in its press release: "Together, these results support the brain tropism of SARS-CoV-2 and its ability to infect neurons. They also suggest that the neurological symptoms observed in COVID-19 could be a consequence of this direct damage to the central nervous system."
The exact entry mechanism into neurons requires further exploration, but the study strongly implicates the ACE2 receptor. Promisingly, it opens doors to prevention strategies, such as blocking ACE2 with antibodies or using cerebrospinal fluid from recovered patients. Ongoing research will validate these approaches.
