New clues about who will develop long covid

These are among risk factors identified in new studies that potentially put someone at greater risk of developing chronic COVID-19, a condition characterized by widespread symptoms such as fatigue, brain fog and a racing heart rate during early COVID-19 infection. persist even after months.

The studies help scientists advance their understanding of the biology behind the long-standing covid, and provide clues to potential treatments. For example, patients with autoantibodies may find relief from existing treatments for lupus, an autoimmune disease.

There may be many reasons for one person to have covid for a long time and another may not confirm the growing belief of scientists that there will be no single cause or treatment for the condition.

“This is really important because we don’t really understand the exact biological risk factors for long-term COVID,” says Linda Geng, co-director of the Stanford Post-Acute COVID-19 Syndrome Clinic. studies.

In a study published in the journal Cell, scientists identified four risk factors for which scientists tested on a patient’s initial diagnosis. The most prevalent one was the presence of certain autoantibodies, which are antibodies that mistakenly attack the body in autoimmune conditions such as lupus. Researchers found autoantibodies in about 60% of patients who had developed covid for a long time.

Most patients did not have a diagnosis of autoimmune disease, but very low levels of autoantibodies associated with various autoimmune diseases, says Jim Heath, senior author of the study and president and professor of the Institute for Systems Biology, a non-profit biomedical research organization. Was. in Seattle.

The second risk factor was reactivation of the Epstein-Barr virus. Epstein-Barr is the one that causes mononucleosis and infects about 90% of people. Normally, the virus remains dormant afterwards. The study found that it was reactivated in some people who later developed covid for a long time.

“Your immune system is probably doing a proper job of keeping EBV under control and with a SARS-CoV-2 infection you lose that brake,” says Dr. Heath. “It seems to happen very early in the transition.”

Two other risk factors were type 2 diabetes and the detection of genetic material from SARS-CoV-2 in the blood, which means the virus has escaped from the lungs and is spreading to other parts of the body.

Researchers collected and analyzed blood and swab samples from more than 200 COVID-19 patients for two to three months after infection. Most of the patients were hospitalized for COVID, but the tests were repeated on a different group of roughly 100 patients with largely mild COVID-19 infection. In a control group, about 460 healthy people were also tested.

The researchers are hoping to use their findings to identify potential treatment options to prevent long-term COVID-19. For example, people who have the virus in their blood may be treated with one of the newer COVID antiviral drugs.

Researchers also found that some long-term covid patients have very low levels of the hormone cortisol, resulting in Addison’s disease, which is characterized by symptoms such as fatigue and muscle pain. Addison’s patients are often treated with cortisol replacement therapy.

The finding is important because doctors can test and treat the problem with existing treatments, says Claire Steves, a geriatrician and clinical academic at King’s College London who also studies risk factors for long-term COVID-19.

Timothy Heinrich, an associate professor of medicine at the University of California, San Francisco who has been studying COVID patients for a long time, said the cell study was well done. But he said it only sees patients two to three months after their initial infection.

In a separate new study in Nature Communications, researchers in Switzerland found five different factors that they concluded would help predict who would develop a longer covid.

Most prominent: lower levels of two types of immunoglobulins, IgM and IgG3, which are types of antibodies, says Onur Boymann, senior author of the study and professor and chair of clinical immunology and allergy at the University of Zurich.

Other predictors included being older, a history of asthma, and symptoms of fever, fatigue, cough, difficulty breathing, and gastrointestinal issues during an acute COVID-19 infection. People who developed covid for a long time had an average of three symptoms during their initial infection.

The researchers looked at 175 COVID-19 patients and compared the findings to about 40 healthy controls. They confirmed the findings in a separate cohort of 395 COVID-19 patients. Some people had all the risk factors while others had fewer, says Dr. Boyman.

The goal, says Dr. Boyman, was to find indicators in the body that were easy to test for. The two immunoglobulins they identified are fairly stable, he says, and are not related to SARS-CoV-2 infection.

In the third study, published in the journal Gut, researchers in Hong Kong analyzed the gut microbiomes of more than 100 COVID-19 patients at the time of their initial infection, one month later, and again six months later. They compared the results to a control group of 68 healthy people.

The gut microbiome is the bacteria and other microorganisms that live in our digestive system. Researchers found that COVID-19 patients with healthy gut bacteria were less likely to develop covid over a longer period of time and had a microbiome similar to those in the healthy control group. Patients who developed covid for a longer period of time had less diverse and abundant microbiomes.

“It is an interesting hypothesis that the gut microbiome may be involved in the process of prolonged COVID,” said Dr Steves, who was not involved in the study. He said that in general when people are sick their microbiome changes, so more data is needed to see whether changing the gut microbiome might work as a treatment.

While promising, the findings of all studies need to be further tested in larger groups of people, says Steven Dix, a professor of medicine at the University of California, San Francisco, who was not involved in the study and is leading a separate study. Study on covid.

“When you study a million things in a few people you find a lot of things and it’s not all that real,” says Dr. Deeks.