The results of this study show that these four factors make it more likely that COVID will last a long time.

The blood of a patient can be tested for several of these factors.

 

After the initial COVID-19 infection clears up, COVID symptoms can last for weeks or months. Scientists have found four risk factors that may help predict who will get persistent COVID.

 

Autoantibodies, immune molecules that target the body's proteins rather than viruses or bacteria, and a previous diagnosis of type 2 diabetes, the most common form of diabetes, in which cells are resistant to insulin, are all risk factors. Another is a high amount of SARS-CoV-2 genetic material in the blood early in infection.

 

This new study, published on January 24 in the journal Cell, suggests that prompt interventions may prevent some cases of protracted COVID because most of these risk factors can be pointed out when a patient is first diagnosed with COVID-19.

 

This research is, however, merely the first step. In an email to Live Science, the author, Yapeng Su, who was at the time a research scientist at the Institute of Systems Biology in Seattle, said that more research is needed to find out if these risk factors cause long COVID and if these early warning signs can help predict which symptoms might still be present in patients four, eight, or 12 months later.

 

Dr. P. J. Utz, a physician-scientist and professor of medicine at Stanford University who was not involved in the study, stated, "I think it's a very well-done study."

 

The National Institutes of Health are funding a multi-center study of long-term COVID, and Utz is one of several Stanford academics who will serve as primary investigators (NIH). Utz remarked that Su undertook the preliminary research and his colleagues "gives us a terrific signpost" for approaching the much bigger RECOVER Initiative, which will involve tens of thousands of patients.

 

Understanding the Potential Dangers

 

About 70% of the patients in the new study had been hospitalized because of COVID-19, and they were followed for two to three months after diagnosis. Long COVID, also known as "post-acute sequelae of COVID-19" (PASC), is a medical term for the effects that SARS-CoV-2 can have on the body after the initial COVID-19 infection has passed. The purpose of this study was to identify similar qualities among the patients who went on to develop long-term COVID.

 

Blood and nasal swabs samples were collected from study participants upon diagnosis, during their COVID-19 infections, and several months later. During this final follow-up, patients filled out a questionnaire on their experiences with long-term COVID symptoms such as coughing, feeling tired, having trouble breathing, having diarrhea, having memory problems, having difficulty focusing, and losing their sense of taste and smell.

 

The study's lead investigator and head of the Institute for Systems Biology, Jim Heath, told The New York Times that 37% of patients experienced three or more COVID symptoms at their final follow-up, 24% reported one or two symptoms, and 39% said none. According to the study's authors, the most common viral symptoms were those affecting the respiratory system, those involving the nervous system, the senses of smell and taste, and finally, the digestive system.

 

Heath told The New York Times that 95 percent of people with three or more chronic COVID symptoms also demonstrated at least one of the four newly identified risk factors. Long-term COVID was associated with the same four risk factors, whether the initial infection was severe or mild. Some of these results were supported by an analysis of blood samples from 100 people who had recovered from COVID-19 infections that were very severe.

 

Illnesses of the digestive tract and the lungs are linked to antibodies.

 

The scientists found autoantibodies in the patient's blood samples as a prominent risk variable. They did a thorough check for a total of six autoantibodies and found that different antibodies seemed to be linked to a wide variety of long-term COVID symptoms.

 

In this case, the autoantibody anti-IFN-2 at the diagnosis predicted future respiratory symptoms in patients with long-term COVID. Anti-IFN-2 antibodies recognize interferon alpha-2, a chemokine that regulates the behavior of some immune cells. The study's authors said that having anti-IFN-2 antibodies could make these immune cells work less well and cause them to make more inflammatory chemicals.

 

Researchers looked for five other autoantibodies, called antinuclear antibodies, that attach to proteins in the cell's nucleus and anti-IFN-2.

 

He said whether these five antibodies cause damage to cells or serve as a sign of disease in autoimmune conditions like lupus and rheumatoid arthritis is unknown. However, "good proof that they are harmful in and of themselves" is lacking.

 

The researchers discovered that the antinuclear antibodies were associated with long-term COVID symptoms, including respiratory and gastrointestinal issues.

 

Neurological symptoms and antibodies

 

But "neurological PASC is not significantly related to these six autoantibodies that we detected," as Su put it.

 

Instead, antibodies targeting the coronavirus appeared to be associated with neurological symptoms. Antibodies against the virus's so-called nucleocapsid were discovered in large numbers only after infection when the chronic COVID symptoms had already developed. Antibodies targeting coronaviruses don't typically show up until after the diagnosis, so they wouldn't be accommodating for predicting the onset of neurological long-term COVID symptoms in advance.

 

According to Utz, the antibody data suggests that distinct processes drive the various long COVID subtypes. As he put it, "we'll be able to look at thousands of people" in the forthcoming RECOVER Initiative to see if it holds.

 

Conflicts in cognition and Epstein-Barr virus

 

The researchers observed that EBV emerged as another critical risk factor for prolonged COVID.

 

According to the clinical resource UpToDate, 90-95 percent of the population will contract EBV at some point in their lives. Following the first infection, the virus goes dormant and hides in the body's immune cells. But this latent EBV can "reactivate," or turn back into active infection if the host is exposed to another virus or goes through a lot of physical or mental stress.

 

Unlike autoantibodies, reactivated EBV was associated with a subset of chronic COVID symptoms. Patients with EBV in their blood when they were diagnosed, for example, were more likely to have memory problems. They were also more likely to feel tired and cough up sputum, a thick mixture of saliva and mucus in the lungs.

 

The presence of EBV fragments in the blood "is a marker of their reactivation," as Su put it. Interestingly, EBV levels in patients' blood tend to peak during their COVID-19 diagnosis and rapidly decline. Su added, "We do not have a clear answer about why this occurs." Still, EBV may have a brief opportunity to reactivate and cause lasting damage when the immune system rallies to attack the coronavirus.

 

According to a 2021 review published in Frontiers in Immunology, EBV infection may produce lupus in people carrying specific genes. Live Science revealed earlier this month that scientists had released persuasive evidence that the virus may cause multiple sclerosis. This inflammatory illness affects the brain and spinal cord in vulnerable individuals.

 

"We know that EBV plays a significant role in lupus, and now we know it does so in MS," Utz added. As shown by the present study, "I will not be shocked if it ends up being right." he stated, referring to the possibility that EBV may potentially have a role in extending COVID. The new study seems to add to the evidence from a small study published in June 2021 in the journal Pathogens. That study suggested that COVID-19 might activate EBV in some patients, making it more likely that they will have COVID for a long time.

 

Coronavirus RNA and Type 2 Diabetes

 

In this study, type 2 diabetes affected about 35% of patients with lengthy COVID. Those with this risk factor were more likely to have fatigue, cough, and other respiratory viral COVID symptoms.

 

One-third of long COVID patients had elevated amounts of SARS-CoV-2 RNA in their blood at the time of diagnosis, and these individuals were more likely to have long COVID symptoms linked to memory.

 

The discovery of viral load suggests that long-term COVID could be avoided (or at least lessened) in these patients if antiviral drugs can be used to bring viral loads under control.

 

Su said that the faster the virus is eradicated, the less likely it is that persistent infection or autoimmunity will develop and could cause long-term COVID. However, as pointed out by Utz, not all individuals would benefit from intensive antiviral treatment, given that COVID can affect those with both mild and severe COVID-19 infections.

 

Other Potential Danger Factors

 

In addition to the known four key risk factors for long COVID, the new study also reveals that people with respiratory symptoms of long COVID had abnormally low levels of the stress hormone cortisol. Those experiencing neurological symptoms also have unusually high blood levels of proteins hypothesized to represent disruptions in the circadian sleep-wake cycle.

 

According to Su, cortisol replacement therapy is already being explored in long-term COVID patients so these findings may point to remedies for this condition. However, Utz stressed the importance of clinical trials in determining whether or not these strategies are practical and, if so, for which subtypes of COVID.

 

The new study is limited in several ways and should be seen as just the beginning. Su remarked that the study's narrow emphasis on PASC two to three months after COVID-19 initiation makes it impossible to predict which individuals will go on to acquire chronic PASC. He said that future research would need to monitor COVID-19 patients for extended periods to explain better prolonged COVID episodes that last for four months or longer.

 

He also noted that animal studies would likely be necessary to determine why and how the identified risk variables cause the various kinds of PASC. Further research is needed to determine whether the multiple SARS-CoV-2 genotypes (alpha to omicron) "change the topography of PASC experienced by patients," as he put it.

Reference : https://www.livescience.com/long-covid-four-potential-risk-factors

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