Most individuals who have COVID-19 recover completely within a few weeks. But some people-- even those who had mild versions of the disease-- continue to experience symptoms after their initial recovery.
These people sometimes describe themselves as "long-haulers," and the conditions have been called "post-COVID-19 syndrome" or "long COVID-19." These health issues also are sometimes called "post-COVID-19 conditions." These health issues are usually considered to be effects of COVID-19 that continue for more than four weeks after people have been diagnosed with COVID-19.
Older individuals and people with many serious medical problems are the most likely to experience lingering COVID-19 symptoms, but also young, otherwise healthy people can feel ill for weeks to months after infection.
Common signs and symptoms that linger over time include:
Organ damage caused by COVID-19
Although COVID-19 is seen as an illness that mainly affects the lungs, it can damage many other organs, as well. This organ damage might increase the risk of long-term health problems.
Organs that might be impacted by COVID-19 include:
Heart
Imaging tests taken months after recovery from COVID-19 have shown lasting damage to the heart, even in people who experienced only mild COVID-19 symptoms. This might increase the risk of cardiac arrest or other heart problems in the future.
Lungs
The type of pneumonia commonly associated with COVID-19 can cause long-lasting damage to the small air sacs, or alveoli, in the lungs. The resulting scar tissue can lead to long-term breathing problems.
Brain
Even in young people, COVID-19 can cause strokes, seizures and Guillain-Barre syndrome-- a condition that causes temporary paralysis. COVID-19 also can increase the risk of getting Parkinson's disease and Alzheimer's disease.
Some adults and children experience multisystem inflammatory syndrome after they have been infected with COVID-19. In this condition, some organs and tissues become severely inflamed.
Blood clots, blood vessel problems
COVID-19 can make blood cells more likely to clump and form clots. While large clots can trigger heart attacks and strokes, much of the heart damage caused by COVID-19 is believed to come from small clots that block small blood vessels, or capillaries, in the heart.
Other parts of the body affected by blood clots include the lungs, legs, liver and kidneys. COVID-19 also can weaken blood vessels and cause them to leak, which contributes to potentially long-lasting problems with the liver and kidneys.
Problems with mood, fatigue
Individuals that have severe symptoms of COVID-19 often have to be treated in a hospital's ICU with mechanical support, such as ventilators to breathe. Merely surviving this experience can make an individual more likely to later develop post-traumatic stress disorder, depression and anxiety.
Because it's hard to predict long-term outcomes from COVID-19, scientists are examining the long-lasting effects seen in similar viruses, such as the coronavirus that causes severe acute respiratory syndrome, or SARS.
Many individuals that have recovered from SARS have gone on to develop chronic fatigue syndrome, a complicated condition characterized by severe fatigue that worsens with physical or mental activity but doesn't improve with rest. The same might be true for individuals that have been infected with COVID-19.
COVID-19 effects still not known
Much is still unknown regarding how COVID-19 will affect individuals over time, but research is ongoing. Scientists recommend that health care providers closely monitor people who have been infected with COVID-19 to see how their organs function after recovery.
Several large medical centers are opening specialized centers to care for individuals who have chronic symptoms or similar illnesses after they recover from COVID-19. Support groups are available, as well.
It's important to keep in mind that most people who are infected with COVID-19 recover quickly. But the potentially long-lasting problems from COVID-19 make it even more important to reduce the spread of COVID-19 by following preventative measures. This includes wearing masks, social distancing, avoiding crowds, receiving a vaccine when available and keeping hands clean.