En español | Millions of people who have been diagnosed with COVID-19 in the past year have reported new or lingering — and sometimes unusual — symptoms of illness, long after their initial infection. In fact, it's become so common that clinics have popped up all over the country to study the phenomenon and help these so-called long-haulers get back to normal.
Here's what we know so far about what doctors are calling “long COVID” — and what we are still hoping to learn.
It can happen even if you have a mild case of COVID-19
When the faculty at the George Washington (GW) University School of Medicine & Health Sciences launched its COVID-19 Recovery Clinic late last summer, they did so with hospitalized patients in mind, knowing that those who were severely ill would likely have a longer road to recovery. What the clinic's founders didn't expect, however, was that post-COVID problems were “just as profound” in people who had mild to moderate cases of the disease, says Monica Lypson, professor of medicine at GW and co-director of its COVID-19 Recovery Clinic.
"Right now, the majority of our patients have not been hospitalized,” she says.
This is not unique to GW's clinic. Jennifer Possick, medical director of Yale's Post-COVID Recovery Program, notes a similar trend — and so does Greg Vanichkachorn at the Mayo Clinic.
"We certainly do have some patients that had severe illness or were even in [intensive care], but that's not the majority of our population by any stretch of the imagination,” says Vanichkachorn, an occupational medical specialist who leads the Mayo Clinic's COVID Activity Rehabilitation Program.
A handful of studies support what health care providers are seeing — that the virus can haunt people who were hardly affected by its initial infection. For example, a July 2020 report from the Centers for Disease Control and Prevention (CDC) found that 20 percent of previously healthy 18- to 34-year-olds who had COVID-19 and were not hospitalized still weren't back to their usual state of health two to three weeks after testing positive for a coronavirus infection.
Swedish researchers discovered that 26 percent of young and otherwise healthy health care workers who had mild COVID-19 had at least one moderate to severe symptom for at least two months after their infection; 11 percent had at least one symptom that lasted eight months. Similarly, a pre-print study looking at health records in California found that 27 percent of people who were never hospitalized for COVID-19 reported ongoing symptoms after 60 days.
Long COVID is not uncommon
It's hard to pinpoint exactly how many people experience new or persistent symptoms after a coronavirus infection, says Mark Avdalovic, a pulmonary and critical care specialist at University of California Davis Health. But it's something researchers are hoping to better understand.
An early study published on long COVID found that more than 87 percent of 143 hospitalized patients with COVID-19 reported at least one persistent symptom following their initial diagnosis. Other reports, however, show that the population affected is likely much smaller. A U.K.-based survey found that 13.7 percent of more than 20,000 participants who tested positive for COVID-19 continued to experience symptoms for at least 12 weeks after the infection. Other experts estimate that about 10 percent of the population who had COVID-19 have lingering symptoms.
Common Long COVID Symptoms
- Tiredness or fatigue
- Difficulty thinking or concentrating (sometimes referred to as “brain fog")
- Loss of smell or taste
- Dizziness on standing
- Fast-beating or pounding heart
- Chest pain
- Difficulty breathing or shortness of breath
- Joint or muscle pain
- Depression or anxiety
- Symptoms that get worse after physical or mental activities
Possick says that since Yale's Post-COVID Recovery Program launched last summer, she and her colleagues have seen “a lot of traffic” — nearly 500 patients to date. But “that's still a very small number,” considering more than 32 million Americans have tested positive for COVID-19 and many of them could be battling unrelenting symptoms.
"The majority of people with COVID are never hospitalized, and a lot of them are younger, they're working age. And so even if only a small fraction of those people has persistent post-COVID conditions, mathematically it's still a lot of people,” Possick says.
The symptoms of long COVID vary
There's really no singular symptom that defines long COVID. People who experience it have reported a range of problems — sometimes multiple symptoms at a time — from shortness of breath to joint and muscle pain.
The most common condition “by far” that Vanichkachorn sees in his patients at the Mayo Clinic is fatigue, where people who were previously active get exhausted after ordinary activities, like walking the dog.
Another frequent symptom among long-haulers is “brain fog,” or difficulty thinking.
"And unfortunately, of all the symptoms that patients find interfere with their lives, this is the one that is the most interfering, because it usually shows up in the workplace — patients are not able to do the things they normally do and end up getting written up or having a performance improvement plan. And that's quite stressful for the patient,” Vanichkachorn says.
GW's Lypson has noted elevated heart rates, persistent cough, and unexplainable numbness or tingling in her long COIVD patients. Heightened anxiety is another prevailing problem, she says.
A recent study published in The Lancet Psychiatry found that as many as one in three COVID-19 survivors experience a mental health or neurological disorder within six months of a coronavirus infection, and that anxiety is among the most commonly reported symptoms.
Some of these ailments, such as brain fog and fatigue, are expected in patients who spend a long time in the hospital with any type of life-threatening illness. But what's puzzling health experts is that they're popping up in people who never needed treatment in the first place.
UC Davis’ Avdalovic says he occasionally sees symptoms stick around after other viral infections. For example, a flu patient might have fatigue that “seems to linger a little bit longer than it should. But not to this degree,” he says. “How frequently we now see [ongoing symptoms in people who had COVID-19] is, I think, somewhat unique.”
Experts still don't know what causes long COVID
"We have theories at this point,” but no definitive answer for why some people experience long COVID, the Mayo Clinic's Vanichkachorn says.
One idea is that the body gets stuck in a hyperimmune state and starts to “fight itself, fight its own nerves, and that leads to all of these complaints,” Vanichkachorn explains. Organ damage from the coronavirus infection may also be to blame for long-term health issues.
Knowing the root cause of long COVID, Lypson says, could make it easier for health care providers to identify patients who are more susceptible to the chronic symptoms, and potentially prevent them from happening in the first place.
People can recover from long COVID
At COVID recovery clinics, multidisciplinary teams of specialists and therapists work with patients to help them overcome their ongoing symptoms. People with prolonged fatigue, for example, work to build their endurance with low-impact activities such as yoga or recumbent exercises.
"We find this is a situation where, if someone pushes themselves too hard and tries to get better in the wrong fashion, that can actually do some damage,” Vanichkachorn says.
Experts have found that making small adjustments, such as writing things down more frequently, can improve day-to-day functioning in individuals with brain fog. And breathing exercises, led by a pulmonologist, can help alleviate lingering lung problems.
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The therapies may take several weeks or months to work, but Possick says most long COVID patients do get better. The important thing is that people who experience lingering symptoms after COVID-19 seek treatment, and that family members, health care providers and employers take the syndrome seriously.
"These post-COVID conditions are real,” Possick says. “And we need to acknowledge them as being a real entity and something that is affecting a lot of people in really significant ways.”
The vaccine could put an end to long COVID
The best way to avoid long COVID is to avoid getting a coronavirus infection in the first place through preventive efforts — such as masks and social distancing in public — and a COVID-19 vaccine, Possick says.
So far about 34 percent of the U.S. population is fully vaccinated, CDC data show. And if more people roll up their sleeves for the shot before the virus has a chance to mutate “out of the current vaccine repertoire,” Avdalovic is hopeful that COVID recovery clinics will be a thing of the past.
"I think if we're successful, then this time next year we're not going to be talking about long-haulers or post-COVID syndrome,” he says. “I'm all for putting me out of business.”
But in the meantime, patience is key while researchers race to find answers.
"What I've noticed a lot is that patients are really anxious, and they're nervous, and they're scared. And it's understandable; they come to the doctor and there's no specific answer,” Avdalovic says. “And so I like to reassure patients that as long as they're slowly feeling a little bit better, and we're taking the time to try and understand what's going on with them, that we are going in the right direction, even if it doesn't feel as definitive as they would like.”
Rachel Nania writes about health care and health policy for AARP. Previously she was a reporter and editor for WTOP Radio in Washington, D.C. A recipient of a Gracie Award and a regional Edward R. Murrow Award, she also participated in a dementia fellowship with the National Press Foundation.
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