Nat. Neurosci. https://doi.org/10.1038/s41593-020-00758-5 (2020)

A common symptom reported by COVID-19 patients is the loss of taste and smell, suggesting that SARS-CoV-2 infection might also affect cells within the central nervous system (CNS). In Nature Neuroscience, Meinhardt et al. show that SARS-CoV-2 virions, RNA and spike protein are readily detectable in nasopharyngeal tissue obtained upon autopsy of deceased patients who had COVID-19. In particular, olfactory sensory neurons in proximity to infected mucosal epithelial cells can become infected, leading to retrograde transport of virions through the cribriform plate into the CNS. The presence of SARS-CoV-2 in the CNS correlates with microglial expression of HLA-DR and the presence of inflammatory cytokines. Higher viral loads correlate with higher detection frequencies in other neuronal cells, including those found in the olfactory bulb and medulla oblongata, a neuroanatomical region that controls respiratory and cardiovascular functions. Some patients also displayed neurovascular tissue damage, evidenced by microthrombotic lesions and infarcted tissue. These findings suggest that direct infection of the CNS by SARS-CoV-2 contributes to the pathology observed in patients with acute infection.