A new study from China shows that more than three quarters of COVID-19 patients who were sent to hospital experienced at least one symptom of the virus six months after first falling ill.

The cohort study, published on Friday in The Lancet, looked at 1,733 COVID-19 patients who were discharged from the Jin Yin-tan Hospital in Wuhan, China between January and May 2020 and found that 76 per cent of them continued to experience at least one of the symptoms six months later.

Among those who continued to experience symptoms, 63 per cent of patients had experienced persistent fatigue or muscle weakness, while 26 per cent had experienced difficulty sleeping and 23 per cent reported depression or anxiety.

“Because COVID-19 is such a new disease, we are only beginning to understand some of its long-term effects on patients’ health,” Prof. Bin Cao, one of the co-authors from the National Center for Respiratory Medicine at the China-Japan Friendship Hospital and Capital Medical University, said in a news release.

“Our analysis indicates that most patients continue to live with at least some of the effects of the virus after leaving hospital, and highlights a need for post-discharge care, particularly for those who experience severe infections. Our work also underscores the importance of conducting longer follow-up studies in larger populations in order to understand the full spectrum of effects that COVID-19 can have on people.”

While all 1,733 patients were interviewed face-to-face six months after infection to gauge their long-term symptoms, some of the patients were also given additional testing, including an endurance walking test and lab tests of kidney function, to name a few.

A total of 349 patients were given a lung function test and 31 per cent of them had reduced lung function, while 23 per cent of the 1,692 people who took the walking test performed poorer than a normal person.

When it came to kidney function, 107 of the 822 patients who had normal kidneys while in the hospital had reduced kidney function six months later.

Another 94 patients were tested for neutralizing antibodies, and researchers found that 53 per cent of them had reduced antibody levels six months after their visit to the hospital. 

“The decline of neutralizing antibodies observed in the present study and other studies raises concern for SARS-CoV-2 re-infection,” the authors note in the study. “The risk of re-infection should be monitored for patients who present with compatible symptoms of COVID-19.”

This research is consistent with some other studies on the long-term symptoms of coronavirus patients. A 2007 study of patients hospitalized from SARS during the outbreak in Toronto found that 33 per cent of the 117 patients had experienced a “significant reduction in mental health” one year after infection, while 18 per cent of these patients also saw a significantly worse score in the walking endurance test.

The researchers in this latest study note that more research is needed when it comes to comparing the long-term side effects of those who were admitted to hospital and those who weren’t.

“Even though the study offers a comprehensive clinical picture of the aftermath of COVID-19 in hospitalized patients, only 4 per cent were admitted to an intensive care unit (ICU), rendering the information about the long-term consequences in this particular cohort inconclusive,” the authors wrote in the news release.

“Nonetheless, previous research on patient outcomes after ICU stays suggests that several COVID-19 patients who were critically ill while hospitalized will subsequently face impairments regarding their cognitive and mental health and/or physical function far beyond their hospital discharge.”