A major study on the impact of COVID-19 on the brain indicates even a mild case can significantly affect the complex organ, thinning tissue and disrupting functions that control smell and some cognitive abilities.
The findings are sobering for the nearly 2 million New Jersey residents — and 80 million Americans — who have contracted the coronavirus.
The study, published in the journal Nature and described as the first detailed look into the neurological impacts of mild COVID-19, reveal a reduction in brain size and gray matter as well as tissue damage in areas linked to smell, taste and memory among those who had the coronavirus. Those patients also required more time to complete cognitive tests, such as trail-making.
Researchers examined brain scans of 785 people in Great Britain — roughly half had contracted COVID-19 between March 2020 and April 2021 and half had not. They compared scans that had been conducted before the infected participants, who ranged in age from 51 to 81, had contracted the virus with scans that were done nearly five months after the patients were diagnosed.
New scans on volunteers who did not have COVID-19 showed no marked changes, the researchers said.
“Whether this deleterious impact can be partially reversed, or whether these effects will persist in the long term, remains to be investigated with additional follow-up,” the researchers said.
Neurology experts call the results significant, although — like the researchers who conducted the study — they caution that further data needs to be collected before drawing definitive conclusions.
“It’s remarkable,” said Dr. Kyra Blatt, a neurologist with RWJ Barnabas Medical Group. “It looks like the areas that are affected lose volume, and they seem to lose connectivity as well as possible function.
“And then they used neurocognitive testing, which we’ve been using for years here at RWJ Barnabas. What they were seeing was that even some of the places in the brain that were not directly affected by COVID, but were connected and are important for cognition, were also affected.”
Blatt noted that while some of the changes were modest, “they were there.”
The study covered those who had contracted COVID-19 in the first year of the pandemic and did not involve variants such as delta and omicron, raising the question, Blatt added, whether they affected the brain the same way.
The study was also conducted before the wide availability of vaccines, leaving open the question of what difference, if any, inoculation might make.
In general, vaccinated people who contracted COVID-19 fared better overall than unvaccinated people, Blatt said.
“Clinically, I don’t think we’ve had enough [time and data] to find out about the long term, but certainly clinically, those patients do much better,” she said.
“I think this is the beginning of the story, but we need to see more. We want to see more with the variants we have now. We want to see if this continues over time or does it get better? Which treatments help them get better? Hopefully we’ll learn more so that we can tailor treatments.”
Dr. William T. Hu, associate professor and chief of cognitive neurology at Rutgers-Robert Wood Johnson Medical School, agrees that the British study is compelling, but many important questions remain unanswered.
“The results need to be interpreted with caution,” Hu said, adding that he and colleagues have received numerous calls from “concerned patients with long COVID.”
The researchers did not know whether the participants had long COVID, according to The New York Times, making it difficult to discern if that condition — in which people have chronic health problems that continue long after the initial coronavirus infection — played any role in the changes of some patients’ brains.
“One key question,” Hu said, “is whether we can find a predictor, or baseline” for who is most at risk after a COVID-19 infection.
“Some people continue to have persistent symptoms, now almost two years after the initial infection, whereas some other people, after an initial six months or so, their symptoms start to improve,” said Hu, who is studying brain fog and dementia in coronavirus patients. “We don’t know how they’re different, because when we assessed their cognition early on, they look pretty similar to each other.”
Such information, he said, could help “get them treatment sooner.”
Both Hu and Blatt said COVID-19′s impact on the brain could have worrisome implications for society at large, especially if a sizable number of people have cognitive and physical impairments.
For instance, experts believe as many as 30% of those who contract the coronavirus develop long COVID. In the U.S., that would amount to 24 million. If a similar number suffer cognitive issues, spiraling medical bills and the loss of productivity would resonate in the economy.
Hu and Blatt also raised concerns that patients who have lingering health issues after a coronavirus infection aren’t taken seriously when they seek disability benefits or medical treatment.
“There’s a lot of misconception that’s very similar to the misconception over chronic fatigue,” Hu said, adding that even some physicians can be dismissive when patients complain about their condition.
“The one thing that frustrates us is that these are people who are not feeling well, and in addition to looking for ways to get better and participating in research, they have to defend themselves against family and health care providers who say, ‘There’s nothing wrong you.’”
Blatt hopes studies like this bolster the credibility of those who argue that COVID-19 takes a lingering toll on many patients.
“As someone who’s fought with insurance companies, I’m hoping that this gives us some backing. Patients are not just milking this,” she said. “My patients want to get better and go back to their lives.”
The brain study is just the latest on the lingering impact of COVID-19 on the body.
One study published earlier this year, for instance, found that a number of coronavirus patients mysteriously developed cardiovascular disease weeks or even months after being diagnosed.
“We know that there are many patients — somewhere between 10% and 30% — who have had COVID and are still suffering,” said Dr. David Landers, the associate director of the Heart & Vascular Hospital at Hackensack University Medical Center. “So the COVID phenomenon can be a durable one and persistent.”
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Elizabeth Llorente may be reached at ELlorente@njadvancemedia.com. Follow her on Twitter @Liz_Llorente.