(CNN) -- It doesn't end with a negative test.
COVID-19 survivors are discovering scary long-term effects of the disease.
Strolls that feel like climbing Mount Everest. Brain fog and problems with short-term memory make reading, writing and speaking harder. Chronic fatigue, breathlessness, and muscle pain turn simple everyday tasks into difficult chores. Returning to work is out of the question.
In Europe, where the peak of COVID-19 infections has now passed, thousands of people said they are far from fully recovered. Health authorities are starting to offer rehabilitation services to survivors suffering from wide-ranging effects of the disease.
"What surprises me the most is that even the patients that have not spent any time in the ICU are extremely feeble," said Dr. Piero Clavario, director of a post-COVID rehab institute in Genoa, Italy. "There is no evidence of a cardiological or pulmonary problem, but they are not even able to walk up a flight of stairs."
Clavario said some of patients also show serious muscle weakness.
"A 52-year-old nurse had to go back to work after having recovered from COVID, but she just couldn't physically make it," he said.
When the pandemic first ravaged the world, it was mostly older people who were thought to be the most at risk. However, more younger people are now getting infected. And many are reporting lingering health problems months after contracting the disease.
Research now indicates that COVID-19 is a multi-system disease that can damage not only the lungs, but the kidneys, liver, heart, brain, nervous system, skin and gastrointestinal tract. And while it is still true that the majority of cases are relatively mild, roughly 20% suffer severe symptoms.
"One out of five patients are going to get a severe form of the disease," said Dr. Luis Ostrosky-Zeichner, a professor of medicine at the University of Texas McGovern Medical School. "This is a lottery you do not want to win."
YOU ASKED. WE ANSWERED
Q: How long do I need to isolate to prevent transmission of the virus?
A: The US Centers for Disease Control and Prevention has updated its guidance for people who are isolating at home with COVID-19 to prevent transmission of the virus.
Someone who has tested positive for COVID-19 and has symptoms may discontinue isolation 10 days after the symptoms first appeared, so long as 24 hours have passed since the last fever without the use of fever-reducing medications, and if symptoms such as coughing and shortness of breath have improved.
People with COVID-19 symptoms isolating at home and with access to tests can leave isolation if a fever has passed without the use of medication, if there is an improvement in symptoms, and if tests taken more than 24 hours apart come back negative, according to the guidelines published Friday.
A person without symptoms can discontinue isolation 10 days after the first positive test and if they have not subsequently developed symptoms. People who have tested positive for COVID-19 and are asymptomatic can also discontinue isolation if the results of two tests taken more than 24 hours apart come back negative.
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