The devastating neurological effects of prolonged Covid can linger for more than a year, according to research published Tuesday, even as other symptoms subside.
The study, published in the Annals of Clinical and Translational Neurology, is the longest follow-up study of neurological symptoms among long-term COVID patients who were never hospitalized for COVID.
Neurological symptoms, including mental confusion, numbness, tingling, headache, dizziness, blurred vision, tinnitus, and fatigue, are the most common of the disease.
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The new study, from researchers at Northwestern University, is a follow-up to a short-term study published last spring that focused on 100 patients with prolonged Covid. That research found that 85 percent of patients reported at least four lasting neurological problems at least six weeks after their acute infections.
For follow-up, the team went on to survey 52 of the original participants, who were patients at the university’s Neuro COVID-19 Clinic, a longstanding Covid clinic, for up to 18 months. Three quarters of the cohort were women and the average age was 43 years. Nearly 80 percent were vaccinated and all had mild Covid symptoms that did not require hospitalization.
Most neurological symptoms persisted after an average of 15 months, the study found. Although most patients reported improvements in their cognitive function and fatigue, the symptoms had not completely disappeared and were still affecting their quality of life.
“Many of these patients still have difficulties with their cognition that prevent them from working like they used to,” said study co-leader Igor Koralnik, MD, chief of neuroinfectious diseases and global neurology at Northwestern Medicine, who oversees the Neuro COVID-19 Clinic. .
The study also found that some symptoms, including heart rate and blood pressure variation, as well as gastrointestinal problems, increased over time, while loss of taste and smell tended to improve. Vaccination against covid did not relieve symptoms, but it did not make covid worse for long either.
The Northwestern study did not look at why some symptoms persist and others go away or why they occur in the first place.
“The next step for this is to find out what causes prolonged covid in the first place and why some people get it and others don’t,” Koralnik said.
Dr. Avindra Nath, clinical director of the National Institute of Neurological Disorders and Stroke at the National Institutes of Health, who was not involved in the new research, said one hypothesis is that symptoms in prolonged Covid patients are the result of the damage caused by the body’s inflammatory response to the coronavirus. Any viral infection activates inflammatory cells throughout the body, including in the brain. The inflammation is meant to attack the invading virus, but also damages brain cells and neurons in the process. SARS-CoV-2, the virus that causes Covid, triggers a particularly strong inflammatory response, he said.
“Covid is probably the most serious respiratory illness we’ve ever had, so it’s not surprising that we’re seeing long-term effects,” Nath said.
Dr. Panagis Galiatsatos, an assistant professor of medicine and pulmonary and critical care physician at Johns Hopkins Medicine in Baltimore, who was not involved in the study, said continuing to track long-lasting symptoms is crucial to help experts tease out long-term symptoms. of Covid of those of the natural healing process. That, he said, will inform future research exploring treatment and, hopefully, ways to provide early diagnosis.
Galiatsatos said it is normal for a patient to experience fatigue and other symptoms during the normal recovery process after an infection, because fighting a virus is difficult for the body. “But the healing shouldn’t take six months or more,” he said.
“Right now we need time to distinguish between the two groups,” he said. “Patients have to wait, and that’s really frustrating. But if we had biomarkers to test, we could identify prolonged Covid and intervene early.”
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The search for biomarkers, however, has not yielded results so far.
In a separate study, published Monday in the Annals of Internal Medicine, researchers from another branch of the NIH, the National Institute of Allergy and Infectious Diseases, performed comprehensive medical exams on 189 long-term Covid patients.
The exams included more than 130 cognitive, blood and imaging diagnostic tests. They also looked for biomarkers indicating heart and brain damage, as well as kidney and liver damage.
The results were compared with the same tests carried out on 120 people without long-term Covid; no differences were identified.
“Despite extensive investigation,” said study lead author Dr. Michael Sneller, an infectious disease specialist at NIH, “we were unable to demonstrate any evidence of organ damage” or other physical differences.
That should not be interpreted to mean that long-term Covid patients aren’t experiencing true illness, Sneller said. Something is happening; modern medicine has so far simply been unable to understand what is going on.
“Make no mistake, these people are really hurting,” he said. “We are not going to give up.”
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