Brain fog after COVID-19 has similarities to ‘chemo brain,’ Stanford-led study finds

Stanford University School of Medicine researchers studied mice with mild SARS-CoV-2 infection and postmortem human brain tissue collected early in the pandemic to find that inflammation damages the same brain cells and processes as cancer chemotherapy, leading to cognitive impairment.

• The overlap between COVID-19's cognitive aftermath and chemo brain may speed research on treatments, Monje said.
• Monje's team has spent two decades studying cognitive impairment after cancer, and found that damage to myelin slows the transmission of nerve signals.
• Researchers studied brain changes in mice after mild respiratory infection with H1N1, the viral strain that caused the 2009 "swine flu" and 1918 "Spanish flu" pandemics. They found that the brain changes were similar to those seen after COVID-19 infection, but were shorter-lasting and less severe.
• Researchers examined brain tissue from people who died suddenly in New York City in the spring of 2020 and found that those with COVID-19 had greater microglial reactivity than those in the control group, in a pattern that matched what was found in the mice.

Brain fog after COVID-19 has similarities to 'chemo brain,' Stanford-led study finds

Nevertheless, scientists saw more of several inflammatory cytokines in the blood and cerebrospinal fluid of the mice, increases that could be detected one and seven weeks after infection. In their white matter, the microglia - brain cells that support neurons and "eat" cellular debris in the brain - were much more active than normal, an abnormality that persisted seven weeks after infection.

med.stanford.edu