Fig. 1.

Three phases of CNS infection by SARS-CoV-2. First, the virus directly invades the brain through vascular or retrograde axonal transport within the cribriform plate, and thus the viral load increases in the CSF. Second, the virus infects, replicates in, and kills neural cells through ACE-2 receptors and TMPRSS2, a facilitator of viral entry. Finally, in the third phase, the immune-mediated response against the virus can indirectly involve the brain, although the viral replication declines in this last phase. CNS central nervous system, ACE-2 angiotensin-converting enzyme 2, TMPRSS2 transmembrane serine protease 2. Adopted from https://www.dpz.eu/de/infothek/wissen/coronaviren.html, by Markus Hoffmann. Adopted with permission