A sobering addition to the literature on COVID-19 and the brain.

Several COVID-19 studies have focused on neuropathology. In this issue of the JCI, Qin, Wu, and Chen, et al. focused specifically on people whose acute infection lacked obvious neurological involvement. Severely infected patients showed abnormal grey matter volumes, white matter diffusion, and cerebral blood flow compared with healthy controls and those with mild infection. The data remain associative rather than mechanistic, but correlations with systemic immune markers suggest effects of inflammation, hypercoagulation, or other aspects of disease severity. Mechanistic research is warranted. Given the lack of obvious neurological symptoms, neurocognitive assessments were not performed, but the findings suggest that such assessments may be warranted in severely affected patients, even without obvious symptoms. Further, studying CNS involvement of other disorders with overlapping pathophysiologies, such as inflammation, coagulation, hypoxia, or direct viral infection may reveal the causes for COVID-19 related neuropathology.