Are you suffering from long COVID headaches and brain fog? Another coronavirus could be the culprit
If you’re a Long COVID patient with a headache, brain fog or other neurological symptoms, another coronavirus could be to blame — at least in part, according to a new study.
Researchers from the Ragon Institute of Massachusetts General Hospital, the Massachusetts Institute of Technology and Harvard University examined the spinal fluid of 112 patients infected with COVID. In patients with long-COVID neurological symptoms, which included inflammation of the brain with seizures and cognitive deficits, they found evidence of an overwhelming antibody response to COVID — and an overwhelming antibody response to other coronaviruses that usually present as the common cold.
The results suggest that immune imprinting may play a role in patients with neurological long-COVID symptoms, the authors wrote. Also known as “antigenic sin,” immune imprinting is a phenomenon in which a person’s immune system continuously responds to the first version of the virus it sees — even when exposed to a related but different version.
A recent Harvard University study describes similar findings in a small group of patients who had been diagnosed with arthritis or a similar condition before the pandemic and who had since contracted COVID and developed Long COVID.
The blood of such patients showed evidence of an overwhelming antibody response to COVID – and an overwhelming antibody response to OC43, a coronavirus that commonly causes upper respiratory illness. Although its presentation is often mild, the pathogen is known to cause bronchitis, bronchiolitis, and pneumonia in children and the elderly, as well as in immunocompromised patients, and its presentation can be easily confused with that of COVID-19, according to a 2021 article in The Southwest Respiratory and Critical Care Chronicles.
The patients in the later study were likely infected with the virus at some point in their lives before contracting COVID, the authors theorized. When their body’s immune system was exposed to the SARS-CoV-2 coronavirus that causes COVID, they responded with OC43 antibodies, which were similar but not ideal, resulting in chronic inflammation and other long-lasting COVID symptoms.
Immune imprinting could also be why a recent study by Columbia University and the University of Michigan found that new Omicron boosters were no more effective than the original COVID vaccines. In this study, researchers suggested that exposure to the original COVID strain through infection or vaccination might limit their future immune response when faced with a new variant.
While little is currently known about immune imprinting, thanks to COVID, scientists are learning more about the process than ever, said Dr. Kathryn Stephenson, an assistant professor of medicine and an infectious disease expert at Beth Israel Deaconess Medical Center in Massachusetts, on Thursday at a Harvard-affiliated COVID news conference. She was not involved in the study.
“I think we’re in a learning stage right now and we’re probably going to rewrite some textbooks,” she said.
Nearly 20% of American adults who have had COVID — an estimated 50 million Americans — report having COVID symptoms long after their infection has cleared, according to data collected by the US Census Bureau this summer.
Long COVID is roughly defined as symptoms that persist or appear long after the original COVID infection has ended, but a consensus definition has not yet been widely accepted.
Many experts contend that the condition is best defined as a chronic fatigue syndrome-like condition that develops after contracting COVID-19, similar to other post-viral syndromes such as those that can occur after infection with herpes, Lyme disease, and even Ebola . Other post-COVID complications, like organ damage and post-intensive care syndrome, shouldn’t be defined as long COVID, they say.
Coronaviruses, named for their crown-like appearance under a microscope, were discovered in the 1960s. Four types, including OC43, circulate commonly among humans and usually cause the common cold. Three other coronaviruses have more severe symptoms: MERS (Middle Eastern Respiratory Syndrome), which caused an epidemic in 2012; SARS (Severe Acute Respiratory Syndrome), which started an epidemic in the early 2000s; and COVID.
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