COVID linked to lower IQ, poor memory and brain aging

Growing scientific evidence suggests that infection with SARS-CoV-2—the virus that causes COVID—profoundly affects brain health in many ways.

Ziyad Al-Ali, a physician and clinical epidemiologist, wrote an essay for The Conversation – which was later republished by Scientific American — detailing the numerous studies that highlight what he describes as the “indelible mark” that COVID leaves on the brain and its functioning.

Al-Ali, who is the director of the Center for Clinical Epidemiology at the Virginia St. Louis Health System in Missouri, wrote that he has studied COVID at length since the first reports of the disease and before the term was even coined by the medical community.

He explained in his essay that “large epidemiological analyses” show that people who have had COVID are at increased risk of cognitive deficits, including memory problems. A study of people with a mild to moderate form of the virus showed significant, long-lasting brain inflammation and changes that were “commensurate with seven years of brain aging.”

Al-Ali also cited imaging studies done on people before and after their COVID infections that showed “shrinkage of brain volume” and “changed brain structure” after infection. Other research has revealed that people who require hospitalization or intensive care following their COVID infection may develop “cognitive deficits and other brain impairments that are equivalent to 20 years of aging.”

Al-Ali also highlighted a preliminary analysis pooling data from 11 studies showing that COVID increases the risk of developing new-onset dementia in people over the age of 60.

He also noted that autopsies performed on people who died with COVID revealed “devastating damage” to their brains. Autopsies of people who had severe COVID but died several months later from other causes showed that the virus was still present in brain tissue, suggesting that “SARS-CoV-2 is not just a respiratory virus.”

Never miss a story — sign up for PEOPLE’s free daily newsletter to keep up with the best of what PEOPLE has to offer, from celebrity news to compelling stories that matter to people.

Studies evaluating patients hospitalized with COVID who experienced brain fog show that the virus can breach the blood-brain barrier, “the shield that protects the nervous system, which is the control and command center of our bodies,” Al-Ali wrote .

More recently, Al-Ali said, a study published Feb. 29 in New England Journal of Medicineassessed cognitive abilities, including spatial thinking, memory, and planning in nearly 113,000 people who had previously had COVID. “The researchers found that those who were infected had significant deficits in memory and executive task performance,” he wrote.

Deficiencies are observed among people infected with the virus in the early phase of the pandemic, as well as when delta and omicron variants predominate.

According to Al-Ali, the same study found that “those who had mild and cured COVID-19 showed a cognitive decline equivalent to a three point loss in IQ.” Those with unresolved persistent symptoms — such as fatigue and shortness of breath — had a six-point loss in IQ, while people who had been admitted to the intensive care unit for COVID had a nine-point reduction.

Another study in the same issue of New England Journal of Medicineinclusive 100,000 Norwegians, documented impaired memory function at several time points 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, and the effects are now being revealed at the population level,” Al-Ali wrote in his essay.

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