Covid-19 can leave many people with potentially debilitating fatigue months after they've recovered from the illness, research released Thursday found.
The long-term lethargy was reported in patients with symptoms from mild to severe.
"Fatigue is a common symptom in those presenting with symptomatic Covid-19 infection," Dr. Liam Townsend, an infectious disease doctor at St. James's Hospital and Trinity Translational Medicine Institute in Dublin, Ireland, said in a statement.
While Covid-19 symptoms, including fever, muscle weakness, shortness of breath, vomiting and diarrhea, have been well publicized, Townsend said, "the medium- and long-term consequences of infection remain unexplored."
The research, which will be presented at a virtual meeting of the European Society of Clinical Microbiology and Infectious Diseases, is based on 128 former Covid-19 patients. It has not been published in a peer-reviewed journal.
Participants were recruited about 2½ months after their illnesses, when their symptoms were expected to have subsided.
More than half reported lasting fatigue. Researchers looked for certain biological signs that might explain the results, such as white blood cell counts and inflammatory blood markers. They found none.
However, women and those with histories of anxiety or depression appeared to be more at risk, although it's unclear why. Those groups simply may be more likely to discuss their symptoms openly.
"Until we get a much larger, robust database, I don't think we can make any kind of statement about gender," said Dr. Kristin Englund, an infectious disease physician at the Cleveland Clinic. "The numbers are just too small."
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Englund, who wasn't involved with the research, said that while fatigue can be somewhat subjective, measurable physical problems can, indeed, be identified long after the body clears the coronavirus.
"We do see people persisting with lung damage well after their Covid infection. We can see people who've had heart damage from the infection on an echocardiogram," Englund said.
The study found that even people who were never sick enough to be hospitalized reported long-term fatigue.
"This study highlights the importance of assessing those recovering from COVID-19 for symptoms of severe fatigue, irrespective of severity of initial illness, and may identify a group worthy of further study and early intervention," the study authors wrote.