A common symptom of COVID-19 is a partial or complete loss of smell. The virus infects sustentacular cells in the olfactory epithelium and is thought to impair thereby the activity of the sensory neurons in this epithelium. Scientists at the Max Planck Research Unit for Neurogenetics in Frankfurt in collaboration with physicians and scientists at the University Hospitals Leuven (Leuven, Belgium) and hospitals in Bruges and Brussels, Belgium, have now examined tissue samples of nasal mucosa and brain of patients who died from or with a SARS-CoV-2 infection, including the Delta, Omicron BA.1 or BA.2 variants. In a total of more than a hundred COVID-19 patients, the scientists failed to find evidence for viral invasion of the brain. A poorly characterized type of fibroblasts in the olfactory mucosa appears to act as one of several anatomical barriers that shield the brain from the virus at vulnerable interfactes.