Study finds about a third of people with ‘mild’ COVID-19 still have symptoms months later

A recent medical study suggests a third of people who contract a mild case COVID-19 could have symptoms that linger for months.

The data comes from the University of Washington, where researchers studied 177 patients for as long as nine months after they were first diagnosed with the coronavirus. The majority of the group had a mild case of COVID-19 and wasn’t hospitalized.

Of the study participants, about 30% reported lingering symptoms. The most common symptoms that persisted were fatigue and loss of smell or taste. 

Additionally, more than 30% of participants said they had a worse quality of life compared to before getting sick. Eight percent also said they had difficulty with at least one usual activity, such as daily chores.

Though the study group was small in size, researchers said they believe this is the longest follow-up study yet that assess symptoms after COVID-19 infection. 

And, as researchers pointed out in their findings, "Even a small incidence of long-term debility could have enormous health and economic consequences."

Meanwhile, numerous other studies are uncovering potential long-term effects of COVID-19.

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A similar study out of Wuhan, China, where the virus originated, followed COVID-19 patients who had more severe cases and had been hospitalized. Approximately three-quarters of that group still reported symptoms within six months after contracting the virus. 

In that study, more than 60% still experienced fatigue or muscle weakness, while 23% reported anxiety and depression. 

In another study, published Feb. 17 in the journal Skeletal Radiology, images from researchers at Northwestern University detailed the various types of long-term effects of COVID-19, including rheumatoid arthritis flares.

"We’ve realized that the COVID virus can trigger the body to attack itself in different ways, which may lead to rheumatological issues that require lifelong management," said corresponding author Dr. Swati Deshmukh.

RELATED: Medical imaging shows the true scope of long-term effects caused by COVID-19

In another study from the National Institutes of Health, researchers found evidence to suggest that brain damage may be a product of COVID-19. Researchers uncovered blood vessel damage and inflammation in the brains of 19 deceased COVID-19 patients.

And in a study published in Sept. 2020, researchers from Ohio State University found that out of more than two dozen athletes from the university who tested positive for COVID-19, 30% had cellular heart damage and 15% showed signs of heart inflammation caused by a condition known as myocarditis.

Outside of scientific research, many others have informally reported long-term symptoms as well. Since the first reported cases of COVID-19, several support groups have emerged on Facebook consisting of thousands of members calling themselves "long haul survivors."

Like so much else in the pandemic, the scientific picture of so-called long-haulers is still developing. It’s not clear how prevalent long-term COVID problems are or why some patients keep suffering while others do not.

The Centers for Disease Control and Prevention is working to learn more about COVID-19’s long-term effects. "While most persons with COVID-19 recover and return to normal health, some patients can have symptoms that can last for weeks or even months after recovery from acute illness," the agency said. 

According to Johns Hopkins, more than 28 million people have tested positive for the coronavirus in the U.S. since the pandemic started. The death toll is inching closer to 500,000 as of Sunday, the highest of any country in the world. 

Since their approval in December, more than 75 million doses of the Moderna and Pfizer vaccines have been distributed, of which 63 million have been injected, reaching 13% of Americans. Nearly 45 million of those doses have been administered since President Joe Biden’s inauguration on Jan. 20.

The Associated Press contributed to this report. This story was reported from Los Angeles.