Updated on June 7, 2022.
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. Fast forward to 2022, some estimates suggest that 7.7 to 23 million people in the United States have developed long covid, or ongoing health issues at least four weeks after becoming infected.
The latest report from the Centers for Disease Control and Prevention (CDC) shows that COVID survivors have twice the risk for developing a respiratory condition or pulmonary embolism—when a blood clot blocks one or more arteries in the lungs. The May 24 report also found that one in five adults younger than 64-years old who’ve recovered from COVID have at least one condition that may be due to their infection. The same is true for one in four older adults age 65 or older, the CDC reports.
Among the COVID patients who were followed for up to one year after their infection, researchers noted the conditions they developed affected a range of organs and body systems, including the:
- Brain: neurological issues, such as headache, loss of sense of taste or smell, brain fog, vertigo, and stroke as well as psychological symptoms, including anxiety, depression, post-traumatic stress disorder, and psychosis.
- Heart: pounding, rapid or irregular heartbeat, dizziness, chest pain, shortness of breath, heart failure, coronary disease (buildup of plaque in the arteries) and heart attack
- Lungs: cough, shortness of breath, chest pain
- Skin and blood: clotting, bruising, rashes
- Kidneys: increased risk for kidney injury or failure
- Endocrine system: fatigue, weakness, nausea, diarrhea, dizziness, and joint pain as well as other symptoms associated with adrenal insufficiency—when the adrenal glands don't produce enough hormones
- Digestive system: loss of appetite, nausea, acid reflux, and diarrhea
- Musculoskeletal system: fatigue, joint pain, myalgia, and muscle weakness
The CDC pointed out these findings are consistent with other large studies, which suggest that long covid-related conditions affect between 20 and 30 percent of survivors.
A February 2021 study published online in JAMA Network Open found that nearly one-third of COVID-19 patients who were not sick enough to be hospitalized have lingering issues months later.
For the study, University of Washington (UW) researchers surveyed 177 people between 31 and 300 days after they recovered from COVID-19. Nearly 85 percent of these patients had only mild illness. Most of the surveys were completed 210 days after becoming sick, or a median of 169 days later. Overall, 32.7 percent reported having at least one persistent symptom. Among the most common complaints: fatigue, loss of sense of smell or taste and brain fog.
“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.
Researchers are searching for answers
While mild COVID cases often result in full recovery within about two weeks, some survivors, like Frisby, are sick for months. In fact, as of July 2021, long COVID can be considered a disability under the Americans with Disabilities Act (ADA).
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.
Evidence compiled over the past two years have helped identify several risk factors that increase the odds of developing long COVID:
- Preexisting conditions, such as type 2 diabetes and obesity
- Sex—women may be more likely to develop long COVID than men
- Older age
- Having severe COVID (although people with mild cases may also be affected)
- Genetics—DNA could play a role in the risk for long COVID
Being unvaccinated against COVID may also increase the odds for long COVID as there is some evidence that being immunized reduces the risk by up to 50 percent. But research on this has been unconclusive and more investigation is still needed.
What causes long COVID?
Researchers are also still trying to determine what causes long COVID. The reasons may vary from one person to the next but, so far, there are four main theories:
- COVID-19 may result in the production of an antibody that mimics the virus. This may trigger an autoimmune response that causes the immune system to attack its own antibodies.
- Some people may not clear the virus and it may linger in the body and cause symptoms.
- COVID may cause organ damage. In some cases, microclots may form in blood vessels, reducing blood flow. This can lead to tissue damage.
- COVID may disrupt the immune system and reactivate “old” viruses that persist in the body, like Epstein-Barr.
Some people with long COVID may experience symptoms that are tough 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 disorder causes debilitating fatigue and has been linked to dysfunction in mitochondria—the cell’s powerhouses—and to immune system malfunction. 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-19, 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-19 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 post-COVID patients develop new symptoms, Raju says. But others, like Frisby, experience worsened symptoms of preexisting well-controlled asthma—even after a relatively mild bout of COVID-19.
“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. Many wonder when, if ever, they can expect to resume their pre-illness level of function. Whether they are at higher risk for other chronic diseases is also unclear. And no one knows yet if having received certain treatments for severe COVID-19, such as monoclonal antibodies, render a person more or less likely to become a “long-hauler.”
In order to answer these and other questions, studies are underway that delve into the body’s reaction to the virus. Scientists will also follow survivors over time to learn as much as they can about the long-term effects of the disease.
Researchers have called for a multidisciplinary approach and a research focus at clinics like Raju’s that care for post-COVID patients.
Treatment strategies for long COVID aim to manage patients’ specific symptoms but therapies may include steroids or anti-inflammatory medication. Trials are also underway to test new treatments for those with lingering symptoms following COVID infection.
By September 2020, Frisby reported feeling “95 percent better,” noting that he still gets tired earlier in the evening. Beyond that, he says he’s doing okay.
Still, in the wake of his bout with COVID-19, Frisby now needs to take more asthma medications than he did before. And tests of his post-COVID lung function showed impairment, Raju said, which presents another mystery.
“His lung function may go back to normal over time,” Raju says. “But I think that’s still something we’re working to understand.”
