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

Red brain with blue background

By Erin Digitale

Brain fog after COVID-19 is biologically similar to cognitive impairment caused by cancer chemotherapy, something doctors often refer to as “chemo brain.” In both cases, excessive inflammation damages the same brain cells and processes, according to research led by Stanford University School of Medicine.

The discovery, described in a paper that published online June 12 in Cell, relied on studies of mice with mild SARS-CoV-2 infection and postmortem human brain tissue collected early in the pandemic. The findings may help guide treatments for cognitive effects of COVID-19, the scientists said.

“We found that even mild COVID can cause prominent inflammation in the brain that dysregulates brain cells and would be expected to contribute to cognitive impairment,” said Michelle Monje, MD, PhD, professor of neurology and neurological sciences.

Monje shares senior authorship of the study with Akiko Iwasaki, PhD, professor of immunology and of molecular, cellular and developmental biology at Yale University. The study’s lead authors are Anthony Fernandez-Castaneda, PhD, a postdoctoral scholar at Stanford; Anna Geraghty, PhD, an instructor of neurology at Stanford; and Peiwen Lu, PhD, and graduate student Eric Song, both of Yale.

The overlap between what happens in COVID-19’s cognitive aftermath and chemo brain, as it’s colloquially known, could be good news for patients because it may speed research on treatments, Monje said. “The exciting message is that because the pathophysiology is so similar, the last couple of decades in cancer therapy-related research can guide us to treatments that may help COVID brain fog.”