Most people who get coronavirus disease 2019 (COVID-19) recover within a few weeks. But some people — even those who had mild versions of the disease — might have symptoms that last a long time afterward. These ongoing health problems are sometimes called post-COVID-19 syndrome, post-COVID conditions, long COVID-19, long-haul COVID-19, and post acute sequelae of SARS COV-2 infection (PASC).

Post-COVID-19 syndrome involves a variety of new, returning or ongoing symptoms that people experience more than four weeks after getting COVID-19. In some people, post-COVID-19 syndrome lasts months or years or causes disability.

Research suggests that between one month and one year after having COVID-19, 1 in 5 people ages 18 to 64 has at least one medical condition that might be due to COVID-19. Among people age 65 and older, 1 in 4 has at least one medical condition that might be due to COVID-19.

The most commonly reported symptoms of post-COVID-19 syndrome include:

• Fatigue
• Symptoms that get worse after physical or mental effort
• Fever
• Lung (respiratory) symptoms, including difficulty breathing or shortness of breath and cough

Other possible symptoms include:

• Neurological symptoms or mental health conditions, including difficulty thinking or concentrating, headache, sleep problems, dizziness when you stand, pins-and-needles feeling, loss of smell or taste, and depression or anxiety
• Joint or muscle pain
• Heart symptoms or conditions, including chest pain and fast or pounding heartbeat
• Digestive symptoms, including diarrhea and stomach pain
• Blood clots and blood vessel (vascular) issues, including a blood clot that travels to the lungs from deep veins in the legs and blocks blood flow to the lungs (pulmonary embolism)
• Other symptoms, such as a rash and changes in the menstrual cycle

Keep in mind that it can be hard to tell if you are having symptoms due to COVID-19 or another cause, such as a preexisting medical condition.

It's also not clear if post-COVID-19 syndrome is new and unique to COVID-19. Some symptoms are similar to those caused by chronic fatigue syndrome and other chronic illnesses that develop after infections. Chronic fatigue syndrome involves extreme fatigue that worsens with physical or mental activity, but doesn't improve with rest.

Organ damage could play a role. People who had severe illness with COVID-19 might experience organ damage affecting the heart, kidneys, skin and brain. Inflammation and problems with the immune system can also happen. It isn't clear how long these effects might last. The effects also could lead to the development of new conditions, such as diabetes or a heart or nervous system condition.

The experience of having severe COVID-19 might be another factor. People with severe symptoms of COVID-19 often need to be treated in a hospital intensive care unit. This can result in extreme weakness and post-traumatic stress disorder, a mental health condition triggered by a terrifying event.

You might be more likely to have post-COVID-19 syndrome if:

• You had severe illness with COVID-19, especially if you were hospitalized or needed intensive care.
• You had certain medical conditions before getting the COVID-19 virus.
• You had a condition affecting your organs and tissues (multisystem inflammatory syndrome) while sick with COVID-19 or afterward.

Post-COVID-19 syndrome also appears to be more common in adults than in children and teens. However, anyone who gets COVID-19 can have long-term effects, including people with no symptoms or mild illness with COVID-19.

If you're having symptoms of post-COVID-19 syndrome, talk to your health care provider. To prepare for your appointment, write down:

• When your symptoms started
• What makes your symptoms worse
• How often you experience symptoms
• How your symptoms affect your activities

Your health care provider might do lab tests, such as a complete blood count or liver function test. You might have other tests or procedures, such as chest X-rays, based on your symptoms. The information you provide and any test results will help your health care provider come up with a treatment plan.

In addition, you might benefit from connecting with others in a support group and sharing resources.