Updated on September 9, 2024.
Before Russell Frisby, a lawyer in the Washington, D.C. area, contracted COVID-19, he was healthy except for mild, well-controlled asthma, with an active lifestyle that included golf. In March 2020, Frisby was hospitalized with COVID for five days. He survived, but six months later he still experienced persistent symptoms.
At its peak, the illness wore away at his spirits.
“You’re sick. You don’t think you’re making any progress. You don’t know when it’s going to end or what it’s going to mean for your life,” Frisby recalls.
He’s not alone. As of July 2024, about 18 percent of adults in the United States—more than 47 million people—report having had Long COVID at some point, or ongoing health issues that last for at least three months after COVID infection.
About 1 in 4 adults in the U.S. are living with Long COVID and may experience symptoms that limit their daily activity, according to the Centers for Disease Control and Prevention (CDC). While most people with Long COVID improve significantly after about three months, it may take up to six months for other people to see an improvement. Some people may develop health concerns that result in disability.
More than 200 symptoms have been tied to Long COVID. Common ones include fatigue, brain fog (difficulty thinking or concentrating), and post-exertional malaise (PEM). This is worsening of symptoms after physical or mental effort.
Symptoms may affect many different parts of the body. These may include:
Heart and lungs: shortness of breath, difficulty breathing, coughing, chest pain, irregular or fast heartbeat
Nerves: headaches, difficulty sleeping, lightheadedness, pins-and-needles feeling, change in smell or taste, depression, anxiety
Digestion: diarrhea, stomach discomfort, constipation
Other: joint or muscle pain, rash, changes in menstrual cycles
Some people with Long COVID may develop complications that lead to new or worsening health conditions, particularly if they have had severe COVID-19. These complications can affect several areas of the body, such as the heart, lungs, kidneys, hormone system, skin, and brain. Examples are:
- Diabetes
- Heart disease
- Blood clots. These commonly occur in the legs. They can break off and travel to the lungs or brain, which is a medical emergency with the potential to be life-threatening.
- Neurologic or mental health conditions
An analysis of the results of 194 other studies found that almost 25 percent of people experienced fatigue or weakness, and 15 percent had difficulty doing usual activity four months, on average, after COVID-19 infection. The study, published in eClinicalMedicine in 2022, included about 735,000 people who had been hospitalized for severe COVID, as well as those who had not been hospitalized.
“The virus is something that can have a prolonged impact on people’s quality of life, people’s ability to return to work and people’s ability to do the activities they always wanted to do,” says Sarath Raju, MD, MPH, a specialist in pulmonary medicine who is treating Frisby at the Johns Hopkins Post-Acute COVID-19 Team (PACT)—a multidisciplinary medical clinic treating COVID-19 survivors with ongoing medical needs related to the virus.
Risk factors for Long COVID
While mild COVID cases often result in full recovery within about two weeks, some survivors, like Frisby, are sick for months. In fact, if Long COVID “substantially limits one or more major life activities,” it can be considered a disability under the Americans with Disabilities Act (ADA). Major life activities include tasks such as caring for oneself, doing manual tasks, reading, thinking, interacting with others, and working.
Why do some people recover fully and not others?
Researchers are still working to understand the risk factors not only for severe COVID requiring ICU care, Dr. Raju says, but also for “a course that involves prolonged symptoms and a prolonged recovery” after a relatively mild initial illness.
Studies have identified several groups that may be at higher risk for Long COVID:
- Underlying health conditions, such as type 2 diabetes and obesity
- People who are assigned female at birth
- Age 65 or older
- Having severe COVID (although people with mild cases may also be affected)
- Hispanic or Latino
- Being unvaccinated against COVID
What causes Long COVID?
The causes of Long COVID may vary from one person to the next. Some reasons could be:
- COVID may cause the immune system to overreact, leading to continued inflammation that damages tissues.
- The infection may trigger an autoimmune response that causes the immune system to mistakenly attack parts of your own body.
- Some people may not clear the virus and it may linger in the body and cause symptoms.
- Very small blood clots called microclots may form in blood vessels, reducing blood flow. This may damage the lungs, brain, and other organs.
- COVID may disrupt the immune system and reactivate “old” viruses that persist in the body, like Epstein-Barr. This is the virus that causes mononucleosis (mono), which can lead to extreme fatigue.
- Psychological effects of having a serious illness may lead to anxiety, depression, and other mental health concerns, especially for those who have been hospitalized.
Some people with Long COVID may experience symptoms that can be difficult to describe and manage. Their physical exams, routine blood tests, chest x-rays, and heart tests may be normal. In these cases, symptoms may be similar to other chronic conditions, including myalgic encephalomyelitis, commonly known as chronic fatigue syndrome (ME/CFS). This condition causes debilitating fatigue. Some cases of chronic fatigue syndrome have been linked to recent viral infection. Something similar could be going on with COVID survivors.
Finding a path to recovery
When Frisby first experienced coronavirus infection, he developed asthma symptoms that didn’t respond to his usual treatments. After several days, he developed a fever, cough and trouble breathing. He spent five days in the hospital with COVID, though he did not need to be intubated.
About a week after going home from the hospital, Frisby again experienced what felt like a stubborn asthma flare. Though his repeat COVID tests were negative, he needed multiple medications to manage his lung symptoms, including a nebulizer every few hours.
For months, Frisby says, “it was horrible.”
“You’re coughing, and you can barely move,” he says. “It’s not like you can do anything. You’re just there—you can barely get out of bed, and you’re feeling lousy, just overall.”
Some people develop new symptoms after having COVID, Raju says. But others, like Frisby, experience worsened symptoms of preexisting well-controlled asthma—even after a relatively mild bout of the infection.
“We’ve seen patients who weren’t even hospitalized who still have residual shortness of breath,” Raju says. “It comes as a shock, I think, to still be dealing with these issues for a prolonged period of time.”
Reason for hope
It’s still uncertain what people recovering from Long COVID may face long-term. Some may wonder when they can expect to resume their pre-illness level of function. Whether they are at higher risk for other chronic diseases may also be unclear.
To answer these and other questions, studies are underway to find out more about Long COVID, and ways to prevent it. Studies are also looking at which groups people are more affected by Long COVID, how new variants of the virus affect the condition, and how vaccination may help prevent it.
Researchers have called for a multidisciplinary approach and a research focus at clinics like Raju’s that care for people with Long COVID.
Treatment strategies for Long COVID aim to manage specific symptoms as part of a comprehensive rehabilitation approach. Therapies may include steroids or anti-inflammatory medication, and those used to manage symptoms similar to other conditions, like chronic fatigue syndrome or fibromyalgia. Trials are also underway to test new treatments for people with lingering symptoms following COVID infection.
