1 week Ago
In March 2020, Hannah Davis fell ill, and everything changed. Her respiratory symptoms were mild, but the neurological and cognitive fallout was frightening. “I could tell very early on that something was wrong with my brain,” she said after getting sick with COVID-19.
And Davis had quantitative proof — her score for processing speed on a cognitive test dropped from the 96th percentile right before the pandemic to the 14th percentile after her coronavirus infection. Moen looks at brain tissue sections from mice that have been infected with COVID-19 at the lab. Davis had been a prolific creator of art and music using machine learning.
“I used to be someone who is thinking all the time, just had a constant flow of ideas,” she said. “And that’s entirely gone.” Five years later, Davis is one of an estimated 20 million Americans and 400 million people worldwide who have had long COVID, in which symptoms persist or newly develop more than three months after a coronavirus infection.
“Someone who has long COVID has functionally changed as a person,” Davis said. “They’re by necessity a different person ..
. it is a systemic illness that changes everything.” Neurocognitive symptoms of long COVID are among the most common, affecting 18 to 36% of patients — and among the most devastating.
Many people have reported cognitive disabilities, with some having to stop working. And some of these cognitive losses are not limited to people with long COVID; they may also extend to those who quickly recovered from the acute infection. The risk of long-term disability has not disappeared.
In 2025, people are still getting infected with the coronavirus and risking long COVID, joining the ranks of those who have struggled with it for a half-decade. “Even today, my brain has not recovered,” said Davis, now 37. Neuroimaging studies have consistently uncovered changes in the brain following a coronavirus infection, though the sample sizes are often small.
Brain scans of long-COVID patients have found pathological changes to areas involved in movement and cognition as well as changes in resting brain activity. A 2024 study reported extensive demyelination, which strips the protective coating from neurons, in long-COVID patients. The degree of demyelination was associated with depression symptoms.
Studies using high-resolution MRIs have also uncovered structural alterations in different parts of the hippocampus, which is vital for learning and memory, and subtle abnormalities in the brain stem, which may impact autonomic functions related to breathing, sleep and heart function. Other research shows patients with long COVID have profoundly decreased blood flow to the brain when standing compared with healthy people. But a coronavirus infection, even without a long-COVID diagnosis, can leave a mark on the brain.
A 2023 brain imaging study of 223 unvaccinated people who recovered from a mild to moderate coronavirus infection found evidence of prolonged neuroinflammation and alterations to white matter. And researchers have found brain atrophy in areas related to memory and emotion regulation among patients with even mild cases of COVID. We only have data from five years, but researchers worry about the long-term ramifications of the pandemic.
“If you had brain fog once, does that mean that your brain is predisposed to cognitive problems down the road?” said Ziyad Al-Aly, an assistant professor of medicine and a clinical epidemiologist at Washington University in St. Louis. Some studies have found that COVID increases dementia-related and inflammatory biomarkers in the brain.
And, as with other infections, a coronavirus infection may increase the risk of developing dementia or cognitive impairment in adults, according to meta-analyses published in 2024 and 2025. “Those are the things that I worry about,” Al-Aly said. Researchers say long COVID is probably not one illness, but an umbrella term covering 200 different symptoms reflective of the virus’s reach: shortness of breath, chronic cough, nausea, hair loss, muscle aches, racing heart rate and more.
Neurocognitive symptoms are among the most common and disruptive long-COVID symptoms, and they include crushing fatigue, disrupted sleep, impaired decision-making, memory loss and brain fog. Long-COVID patients had pronounced cognitive slowing compared with people who did not develop long COVID, one 2024 study found. But a coronavirus infection could have cognitive consequences even in people who aren’t diagnosed with long COVID.
A 2024 study of 112,964 people showed that people who quickly recovered from COVID still had cognitive deficits equivalent to an IQ loss of three points compared with those who never got COVID. More than 45% of people experiencing long COVID reported cognitive disabilities two years after initial infection compared with just 8.8% before their illness, according to one 2025 study.
Research shows long COVID can affect everyone from children to older adults. “We’re really only at the beginning, I think, of understanding the scope of the problem,” said Michael Peluso, an assistant professor and infectious-disease clinician at the University of California at San Francisco. Long COVID can also bring dysautonomia, an often lifelong dysfunction of the autonomic nervous system that controls involuntary functions such as heart rate, sweating and blood pressure.
Janna Moen views images at her lab at Yale School of Medicine. Cases of postural orthostatic tachycardia syndrome, or POTS, a type of dysautonomia that causes rapid heart rate, fainting and dizziness, sharply increased after the pandemic began. These symptoms can be debilitating, said Janna Moen, a neuroscientist who recently wrote a review about neuroimmune interactions in long COVID that is awaiting peer review.
Moen also knows firsthand. After a coronavirus infection in March 2020, Moen found herself getting out of breath walking across her apartment, and her resting heart rate was elevated for months. She later developed “tingling, pins and needles” in her feet, legs and hands — a sign of neuropathy.
The temperature intolerance and uncontrollable sweating were “a nightmare,” she said. Walking to her laboratory in New York City would leave her drenched in sweat. One summer, she remembers needing to lie down while waiting for a train to stop herself from passing out.
It was “just disgusting,” Moen said. “You don’t want to have to lay on the ground in a New York City subway station.” Then things got worse.
Moen had another bout of COVID, a mild one. But less than two months later, her dysautonomia symptoms worsened, with severe disorientation and confusion. “I was so out of it,” said Moen, now 33.
“And I just never really fully recovered.” She had to leave her first postdoctoral research job. Her story is not uncommon.
More than a quarter of long-COVID participants in one 2024 study had to change jobs primarily because of cognitive issues. Just over half of patients with POTS could not work because of their symptoms, one large 2021 study found. Eric Topol, a professor of translational medicine and the executive vice president of Scripps Research, said he knows people who have been infected within the last three to four months who have long COVID.
“It’s nonstop. People are still getting it,” he said. Repeated COVID infections increase the risk of long COVID or exacerbating its symptoms, research shows.
Severe coronavirus infections requiring hospitalization confer the highest risk of long COVID. But over 90% of people with long COVID had mild or even asymptomatic infections, like Davis and Moen. While people do recover from long covid, progress seems to slow and stagnate after the first few months for those severely affected.
Research shows only 7 to 10% of people with long covid fully recover after two years. “Things are not getting worse, but they’re not getting better. I’m still pretty substantially disabled.
I’m lucky enough that I’m still able to work,” said Moen, who is now researching the neuroimmune basis of long COVID as a postdoctoral scientist at the Howard Hughes Medical Institute conducting research at Yale School of Medicine. Davis has regained her ability to drive and play video games, though she does not believe she will return to baseline. She has co-founded the Patient-Led Research Collaborative, a mostly volunteer group of about 60 other long-COVID patients, and advocates advancing our understanding of long COVID.
She has also published multiple highly cited research papers about long COVID with researchers, including Topol and Al-Aly. “This is, for the most part, a permanently disabling illness that isn’t going to get better without investment in treatments and trials as soon as possible,” Davis said. Getting vaccinated, wearing a mask and improving indoor air quality remain measures people can take to reduce their risk of a coronavirus infection and long COVID, experts said.
And for those with long COVID, certain strategies can help lessen the severity of their symptoms, such as resting and pacing. Finding a community of people who understand can also help. Some examples are the Covid-19 Longhauler Advocacy Project, Long Covid Support and the Dysautonomia Support Network.
For more resources, long-COVID patients recommend organizations such as Solve M.E., the LongCovid Research Consortium, and the Patient-Led Research Collaborative, which has released a 2025 long-COVID fact sheet.
The Sick Times is a publication dedicated to long-COVID coverage and has resources for patients. The Visible app tracks symptoms and activity for long COVID and other complex chronic illnesses. “Someone who has long COVID has functionally changed as a person.
They’re by necessity a different person ...
it is a systemic illness that changes everything.”.
