A growing contingent of Covid-19 patients whose symptoms were initially mild are now facing mysterious long-term neurological problems, including memory and sleep disturbances, dizziness, nerve pain, and what survivors refer to as “brain fog.”
The phenomenon, involving thousands of patients with symptoms lasting months at a time, complicates the Trump administration’s argument that most illness is mild so the U.S. can quickly reopen the economy. These frightening long-term cases aren’t captured in official statistics that show that the vast majority of younger adults survive the virus.
While lingering lung issues might be expected given the nature of the virus, some of the most common and surprising problems involve the nervous system. For Americans with these symptoms, there are few answers available on why they surface, how long they’ll last, and what permanent problems they may cause. Neurologists are only just starting to study the trend.
“A very large number of the symptoms fall within the brain and nervous system,” according to Natalie Lambert, an Indiana University School of Medicine researcher who surveyed more than 1,567 members of an online support group for people with longer-term symptoms in a push to map out their effects.
Adrian Owen, a neuroscientist at Western University in Canada, has been “completely inundated” with emails from people who have found themselves with cognitive problems months after their initial infection, he said in an interview.
“It is becoming completely obvious that many of them are suffering from neurological deficits,” Owen said. “Even if this only affects 10% of people, that can be a massive societal and economic burden a year from now.”
For Eli Musser, a 42-year-old copywriter in Astoria, Queens, the first weeks of Covid-19 were nowhere near as bad as what came later. In late March, Musser came down with a low fever and fatigue for a few days followed by a recurring cough that lasted several weeks.
“And then I got walloped,” he said in an interview.
For months, Musser was so debilitated doing more than sitting on the couch and resting was too much. He’s had tremors and shaking in his arms, dizziness, muscle weakness so severe he sometimes had trouble dressing, panic attacks, and depression. One terrifying day in May, he couldn’t move his legs. In June, he experienced intermittent fits of seizure-like sweating and shaking.
Now, five months after his initial symptoms, he’s still on medical leave and only recently received a diagnosis for his neurological symptoms. Meanwhile, Musser’s fiancée, who also fell ill in March but recovered in about 10 days, spends hours each day caring for him.
“A good guess is it won’t last forever, it’ll get better with time,” Musser said. “But also, how much time? How much better? What can I reasonably expect?”
To get a handle on questions like this, the neuroscientist Owen is working with University of Toronto researchers to survey 50,000 coronavirus patients with lingering neurological symptoms to determine who might be most at risk and what the long-term effects are.
They’re using a series of self-reported questionnaires and brain games done online. Other studies, looking at symptoms more broadly in fewer people and with more detail, are just beginning elsewhere as well.
Many patients have been sharing their experiences in a Facebook group called “Survivor Corps” that today counts more than 96,000 members.
Diana Berrent founded the group after contracting Covid-19 in March. Since then, she’s partnered with Lambert to survey its members. The symptom list they gathered was pages long, including difficulty concentrating or focusing, anxiety, memory problems, heart palpitations, blurry vision, and neuropathy in feet and hands.
With researchers just starting to study Covid-19’s long-term consequences, reliable numbers are hard to come by. A recent federal study found that about 35% of people who tested positive for Covid-19 were still experiencing symptoms two to three weeks later, including many young adults.
While patients 50 and older had the highest risk of long-lasting problems, more than a quarter of those under age 35 had continuing symptoms, including many who had no previous health problems.
Meanwhile, a survey of 143 patients who had been hospitalized for Covid-19 in Italy found that two months later only 12.6% were completely symptom-free, and more than half said they still had 3 or more ongoing symptoms.
There’s no doubt that coronavirus infection can cause nerve complications. One early study from Wuhan, China found that 36% of patients had neurologic symptoms ranging from headache to impaired consciousness.
Since then, researchers have reported a variety of strange neurologic syndromes, ranging from Miller Fisher syndrome, a nerve disease that can paralyze eye muscles, to acute disseminated encephalomyelitis, a nerve-lining inflammation that can resemble multiple sclerosis flareups, to autoimmune encephalitis, and inflammation of the brain’s temporal lobes, which can cause confusion and hallucinations.
But with case reports just emerging, it’s been hard to prove cause and effect.
Even when people clear the virus and test negative, they “can feel out of sorts for weeks and weeks,” almost similar to chronic fatigue syndrome, said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, during a Facebook live interview on July 16th. But it may take a year or more to understand whether the virus produces truly long-lasting complications, he said.
There are logical reasons why people who were hospitalized could have residual neurologic effects lasting for months. These patients may have been so sick that organ failure limited oxygen flow to the brain, said Igor Koralnik, who is chief of neuro-infectious disease at Northwestern Medicine and leads its neurology-focused Covid clinic. Blood clots in the brain or widespread inflammation could also impact brain function, he said.
But the neurological symptoms now being seen in people who had milder cases of Covid-19 are more mysterious. Even the loss of smell that’s been a high-profile symptom of Covid-19 is considered neurologic, likely caused by dysfunction of olfactory nerves or nerve support cells, Koralnik said.
It’s possible, for instance, that small amounts of the virus still remain in outer reaches of the body, hiding out and continuing to wreak havoc. There’s precedent for continuing symptoms with other viruses, including the coronaviruses SARS and Middle East Respiratory Syndrome. Lingering virus has also been posed as an explanation in those settings.
So far, though, there’s not strong evidence that Covid-19 infects the brain.
A more likely scenario is that the body’s immune system continues to fire, even after the virus has been dispatched, according to Dipa Jayaseelan, a consulting neurologist at University College London Hospitals, who has studied neurological complications of Covid-19. In that case, she said, numerous antibodies and immune cells activated by the virus could go awry in subtle ways.
“It isn’t the virus itself, but it’s the body’s reaction to the virus,” Jayaseelan said. “The body goes into overdrive” in fighting Covid-19 and may continue to overreact even after the virus is upended.
Allison Navis, a specialist in neuro-infectious diseases at the Icahn School of Medicine at Mount Sinai in New York, has seen about 50 long-haulers in the last month. She believes there isn’t one common cause, but rather a variety of different explanations. “It’s a big mystery,” she said. “Everyone’s commenting that they’re starting to see this.”
An immune reaction may have caused Musser’s dizziness and vertigo.
After a video consultation this month, Northwestern’s Koralnik diagnosed him with Covid-related inflammation of his inner ear nerves and prescribed a motion sickness drug along with specialized physical therapy. It was “truly relieving” to find out that he had something treatable, Musser said in an email.
Covid-19 patients who continue to grapple with symptoms aren’t alone. Some survivors of SARS and Middle East Respiratory Syndrome reported symptoms like fatigue and depression for years afterward.
Ebola survivors often suffer from everything from headaches to joint pain to eye problems long after they recovered from the disease, studies have found. And Zika virus outbreaks have been linked to an higher incidence of Guillain-Barre syndrome, a rare autoimmune disorder where antibodies attack the nerves, sometimes leading to paralysis.
And while long-term brain and lung damage are key concerns with Covid-19, there is also a growing realization that the virus may cause subtle damage to other organs, including heart inflammation.
Tracking the cause of the neurological issues could take a while, given the difficulty of linking far-ranging immune effects to the virus. During the AIDS epidemic, a surge of patients coming in with dementia kick-started the field’s focus on infectious disease. But it took years after HIV was discovered for the concept of HIV-related dementia to become firmly established in the medical community.
At the National Institute of Neurological Disorders and Stroke, neurologist Avindra Nath said he’s received about 200 emails from patients reporting long-lasting neurological complications, including “brain fog,” burning sensations in the hands and feet, headaches, and sleeping problems.
He’s starting two small studies to look at the neurological complications in detail, and plans to bring in dozens of patients for batteries of tests to figure out what might be going on. He suspects some of the burning sensations reported in patients could be an atypical form of Guillain-Barre syndrome or peripheral neuropathy.
One study will focus on Covid-19 patients whose symptoms are similar to a disease called myalgic encephalomyelitis, a mysterious virus-linked illness better known as chronic fatigue syndrome.
“The effects on the brain are under-recognized at the moment,” Nath said. Finding out what is going on “is all we are thinking about right now. This is the number one top priority.”
For some long-haul patients, exhaustive testing has turned up specific abnormalities. Rachelle McCready, a 57-year-old critical care nurse educator in London, Ontario, was hospitalized for eight days in mid-April after coming down with the coronavirus.
She never needed a ventilator or other extraordinary measures. Still, for weeks after she got out of the hospital, she was so exhausted and out of breath she spent most of the day in bed, too tired to do much more than make coffee or do the laundry.
“It feels like you have been hit by a truck, the truck then reversed and hit you again, and you are recovering from that,” says McCready. “I never would have thought it would still be impacting my life here at month five.”
Even after she recovered enough to return to work on a part-time basis in June, she noticed subtle neurological symptoms including trouble finding words and learning new procedures. After an echocardiogram, a heart nuclear medicine scan, a chest x-ray, and other tests came back negative, doctors finally ordered a lung CT scan in early July.
It found subtle damage to the airway walls in her lungs, a condition linked to lung infections and often found in cystic fibrosis patients. Doctors connected it with the coronavirus and, since then, her doctors prescribed oral steroids and asthma inhalers that have reduced her symptoms significantly, she said.
“People need to know this really isn’t quick for some people,” she says. “I think we are going to be seeing the effects of this for years.”