Though tens of millions of people are considered to be living with long Covid in some form, it’s not yet a condition about which much is known. Studies continue to try to spot patterns in its prevalence, which should eventually provide more clues as to how to combat the condition. Long Covid symptoms can include tiredness, fatigue, difficulty thinking, shortness of breath, chest pain, dizziness, menstrual changes and post-exertional malaise. It is in this context that a new analysis, published last week by the Centers for Disease Control and Prevention and University of Washington, in the journal Emerging Infectious Diseases, has found that Covid-19 is associated with quadruple the risk of developing chronic fatigue.
Researchers examined the electronic health records of more than 4,500 people who had Covid-19 during 2020-2021 and more than 9,000 people who did not have the disease. They found that 9.5% of Covid-19 patients developed fatigue, one of the most common symptoms of long Covid, and that those who had been infected were 1.68 times more likely to develop fatigue than those who were not. “The high incidence rates of fatigue reinforce the need for public health actions to prevent infections, to provide clinical care to those in need, and to find effective treatments for post-acute Covid-19 fatigue,” the researchers wrote.
Another finding was that post-Covid fatigue, encompassing chronic fatigue, was more common among women than men, and more common among older than younger people in an unadjusted model. It was also more prevalent among those with other medical conditions. Researchers noted that chronic fatigue diagnoses continued in the 18 months after Covid-19 detection, suggesting a “persistent effect” but also potentially indicating “a delay in diagnosing fatigue as a separate symptom or diagnosis.”
For the study, researchers said they considered chronic fatigue to be a subset of fatigue,’ and noted it was not necessarily the same as myalgic encephalomyelitis/chronic fatigue syndrome, or ME/CFS, which needs additional symptoms for diagnosis. They said their study criteria did, however, include diagnostic codes used for CFS. ME/CFS is an unexplained syndrome that sometimes occurs after infections and comes with severe fatigue. The condition can worsen after activity, and the CDC (US) recently estimated some 3.3mn adults had it in 2021-2022. ME/CFS has garnered increased attention in recent years as its symptoms can overlap with those of long Covid, spurring hopes for more research and insights into the illness.
A new UK study published in Nature Communications should also be considered in this context. It found that some form of brain injury could be behind the symptoms reported by those with long Covid, and adapting tests and treatments to match could aid progress in tackling the condition. Analysing 203 patients hospitalised with Covid-19 or its associated symptoms, and comparing the results with 60 people without the infection, researchers noticed elevated levels of four brain injury biomarkers – key signs of biological change – in those infected with Covid-19.
“Our study shows that markers of brain injury are present in the blood months after Covid-19, and particularly in those who have had a Covid-19-induced brain complication,” says neuroscientist Benedict Michael from the University of Liverpool in the UK. “This suggests the possibility of ongoing inflammation and injury inside the brain itself which may not be detected by blood tests for inflammation.” These brain complications associated with Covid-19 have ranged from mild (headaches) to potentially life-threatening (seizures, stroke, and encephalitis). As previous research has shown, the consequences can be long-lasting.
