CORONAVIRUS UPDATE: As experts learn more about the novel coronavirus, news and information changes. For the latest on the COVID-19 pandemic, please visit the Centers for Disease Control and Prevention.

There is a lot that we still don’t understand about COVID-19, the disease caused by the SARS-CoV-2 virus that started in Wuhan, China, in 2019 and turned into a worldwide pandemic. Because this coronavirus is a novel virus (a virus that has not been previously identified), scientists and healthcare workers are still in the beginning stages of understanding its effects on the body. But, new research is revealing more every day.

One area that is gaining more attention are the long-term, or lingering symptoms (called sequelae), that some people experience from COVID-19 after “recovering” from the virus. How concerned should you be about coronavirus sequelae? First, it’s important to understand the classic symptoms of COVID-19.

What are the symptoms of COVID-19 and how long do they typically last?

Originally, the most common symptoms of COVID-19 included:

Fever
Cough
Shortness of breath

Experts have since expanded on this list to include these additional possible indicators:

Muscle or body aches
Headache
Fatigue
Loss of taste (ageusia)
Loss of smell (anosmia)
Sore throat
Congestion or runny nose
Nausea or vomiting
Diarrhea

These symptoms typically appear two to 14 days after exposure to the virus, according to the U.S. Centers for Disease Control and Prevention (CDC). The duration of symptoms can be up to two weeks for mild cases and up to six weeks or more for severe cases. What is becoming apparent, however, is that some patients may also experience coronavirus sequelae, or lasting complications that continue far beyond this time frame.

What are coronavirus sequelae?

Sequelae is a term used to describe the aftereffect of a disease, condition, or injury. Any viral infection can cause post-viral syndrome, which involves lingering symptoms (or sequelae) long after you fight off an infection. What those symptoms are—and if you’ll experience them at all—can vary, and may depend on risk factors or your body’s immune response.

Sequelae may be particularly common for coronavirus infections. For example, after the severe acute respiratory syndrome (SARS) outbreak of 2002-2003, one study found that people who were infected with the virus reported feeling fatigue, muscle weakness, and sleeping problems up to three years later. Early evidence indicates that similar symptoms could stick around for some COVID-19 patients as well.

Dr. Anthony Fauci, director of NIH’s National Institute of Allergy and Infectious Diseases, has been vocal about the risks of post-viral syndrome with COVID-19. During a press conference, he indicated that many people with severe COVID-19 experience brain fog, fatigue, difficulty concentrating that affect them for many weeks after recovering from other symptoms.

Research is limited about COVID-19 and post-viral syndrome, but according to a letter from the Journal of the American Medical Association, 87% of 143 previously hospitalized patients in Rome, Italy, reported experiencing at least one persistent symptom for two months or longer; particularly fatigue or difficulty breathing.

Who will experience coronavirus sequelae?

It can be difficult to predict who will experience lingering symptoms, and who won’t. Research is still emerging, and there is not consensus among doctors treating COVID-19 patients.

“What we have learned about SARS-CoV-2, so far, is that post-viral syndrome is not uncommon, especially for those who were hospitalized due to the severity of their infection, those with pre-existing conditions (i.e., diabetes, hypertension, etc.), and potentially those of the female gender,” says Robert Quigley, MD, immunologist and senior vice president and regional medical director of International SOS.

Magdalena Cadet, MD, a New York–based rheumatologist and associate attending at NYU Langone Medical Center says it goes beyond those with severe cases. “Long-lasting complications are not always associated with patients who had serious infections or hospitalization,” Dr. Cadet says. “Sequelae of the disease have been seen in people with mild cases of COVID-19.”

In other words, it’s not yet proven who is affected by sequelae.

What are the symptoms of coronavirus sequelae?

While most people will make a full recovery from COVID-19, there are some lingering symptoms that people should know about. “First and foremost, it’s important to state that this is a novel virus (meaning never before seen) and we are continuing to learn and have much more to learn about it,” says Dr. Quigley. “What we have learned thus far, lingering symptoms can occur and may vary from person to person.”

These symptoms include:

Fever
Fatigue
Muscle or body aches
Joint pain
Weakness
Shortness of breath
Difficulty concentrating (or “brain fog”)
Inability to focus
Reduced memory
Nausea, heartburn, or vomiting
Headache
Difficulty sleeping
Prolonged loss of taste or smell
Hair loss
Erectile dysfunction

Dr. Cadet has seen these symptoms in some COVID-19 patients. “They are simply not able to recover their former energy or activity level pre-COVID-19 infection state,” she says. “There are some individuals who may have long-lasting kidney damage, blood clots, or other problems of the blood vessels and skin as well as worsening hypertension (high blood pressure).”

In addition to post-viral syndrome, COVID-19 can cause long-term organ damage. According to one study, COVID-19 may have lasting effects on the heart. In the study, of the 100 people who recently recovered from COVID-19 and received MRIs, 78 showed cardiac involvement, and 60 had signs of myocardial inflammation; which were independent of preexisting conditions. Evidence also shows that COVID-19 may lead to lasting damage to the lungs, including post-COVID fibrosis.

How long will coronavirus sequelae last?

It may be too early to tell. “Unfortunately, the likelihood and timeframe of experiencing lingering symptoms, among those who contracted COVID-19 and are recovering, is nearly impossible to predict,” Dr. Quigley says. However, he says that with other virus infections “those that acquire [post-viral syndrome] generally improve over time.”

What causes coronavirus sequelae?

There are plenty of mysteries still surrounding the effects of the novel coronavirus disease, but researchers and scientists are beginning to make some predictions as to why the SARS-COV-2 infection may be affecting some people so much worse than others, and it appears there may be a connection to inflammation that COVID-19 can trigger.

“Scientists now know that the SARS-COV-2 utilizes the spiky protein on its membrane to interact and bind to the ACE 2 receptors, which can be seen in the lungs, heart, and various organs to trigger an inflammatory response,” Dr. Cadet says. This inflammatory response can trigger many problems in the body. “When the inflammatory response is in overdrive, a cytokine storm may result in numerous cytokines or chemicals that can cause immune cells to target healthy tissues and organs leading to damage and sometimes death.”

It appears that there may be a connection between sequelae and this inflammation. “There is preliminary evidence that lingering symptoms from a COVID-19 infection could be the result of the body’s inflammatory response,” Dr. Quigley says.

Inflammation can affect major organs, such as the heart and lungs, as well. “Since the ACE 2 receptors in the heart are affected by this virus, inflammation of the heart muscle can occur,” Dr. Cadet says. “Some individuals describe heart palpitations, fast heart rate (tachycardia), irregular heartbeat or chest pressure.”

It remains unclear why some people’s immune system responds this way. “We know that this response is variable depending on multiple (host) factors,” Dr. Quigley says. “In general, the body’s response to a foreign invader is to generate an inflammatory response. Part of the cascade of events includes the release of cytokines, in the blood, which mediate subsequent immune responses against the foreign invader (the virus). In the event where such mediators cross the blood brain barrier and accumulate in the central nervous system, they can activate the primitive regulatory parts of the brain phenomenon, resulting in many of the symptoms seen in post-viral syndrome. This was also observed in select patients who contracted SARS during the 2002-2003 outbreak.”

What should you do if you experience coronavirus sequelae?

If you continue to experience lingering symptoms from COVID-19 that concern you, there are some steps you can take. For post-viral syndrome, treatment focuses on managing your symptoms and may include:

Taking over-the-counter pain relievers such as Tylenol or ibuprofen
Eating a balanced and healthy diet
Getting plenty of sleep and resting during the day as needed
Practicing relaxation techniques such as yoga, massage therapy, and meditation

Maintaining an open dialogue with your healthcare provider is crucial, especially for more serious lingering COVID-19 symptoms. “It is important if you have a COVID-19 infection to keep follow-up appointments with your internists as well as other specialists, including a cardiologist, pulmonologist, neurologist, hematologist, and physiatrist,” Dr. Cadet advises.

Most people who test positive for COVID-19 will make a full recovery and can expect to feel better once the virus has run its course. If you think you’re experiencing lingering symptoms, track them and report them to your physician.