Scientist explains ‘indelible mark’ of COVID brain fog



Growing scientific data indicates that the virus that causes COVID-19 significantly impacts brain health.

According to People, physician Ziyad Al-Aly — who has been researching long COVID since the earliest reports of the disease — outlined in an essay for The Conversation how numerous studies demonstrate the “indelible mark” it leaves on the brain and how it functions.

“The growing body of research now confirms that COVID-19 should be considered a virus with a significant impact on the brain,” he wrote. “The implications are far-reaching, from individuals experiencing cognitive struggles to the potential impact on populations and the economy.”

In his essay, Al-Aly, director of the Clinical Epidemiology Center at the VA St. Louis Health Care System in Missouri, explained that “large epidemiological analyses” indicated a higher likelihood of cognitive deficits, including memory issues, in those who had COVID-19.

A study involving individuals with a mild to moderate virus variant revealed alterations in the brain that “are commensurate with seven years of brain aging” and notable, sustained brain inflammation.

Al-Aly also referenced pre- and post-COVID imaging tests that demonstrated “shrinkage of brain volume” and “altered brain structure” following infection. According to additional studies, individuals with COVID-19 who need hospitalization or extensive care may experience “cognitive deficits and other brain damage that are equivalent to 20 years of aging.”

Al-Aly emphasized a preliminary analysis that combined data from 11 studies and demonstrated that in those 60 and older, having COVID raised the risk of new-onset dementia.

He added that autopsies on those with COVID-related deaths showed “devastating damage” to the brains of the deceased. The virus was found in brain tissue during autopsies of patients who had acute COVID but passed away a few months later for other reasons, indicating that the virus, formally SARS-CoV-2, doesn’t only affect the respiratory system.

Al-Aly noted that a study published on Feb. 29 in the New England Journal of Medicine evaluated cognitive abilities — including spatial reasoning, memory and planning — in approximately 113,000 people with COVID. Researchers found that infected persons had “significant deficits” in memory and executive task performance.

The deficits showed in people who contracted the virus during the early stages of the pandemic and at the time when the delta and omicron variants dominated.

In the same study, Al-Aly claims to have discovered that “those who had mild and resolved COVID-19 showed cognitive decline equivalent to a three-point loss of IQ.” Individuals with untreated, persistent symptoms — like shortness of breath and fatigue — reportedly saw a six-point decline in IQ, while those hospitalized in the intensive care unit experienced a nine-point drop.

In a separate study published in the same issue of the New England Journal of Medicine, 100,000 Norwegians had lower memory performance at various times up to 36 months after testing positive for COVID.

“Taken together, these studies show that COVID-19 poses a serious risk to brain health, even in mild cases,” Al-Aly wrote, People reported, “and the effects are now being revealed at the population level.”

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