An international team of scientists has discovered distinct changes in the blood of people with long Covid, suggesting a potential strategy for diagnosing and possibly treating a mysterious condition that takes many forms.
The important study, published Thursday in the journal Science, adds to our understanding of long Covid, and the persistent and often debilitating symptoms that some people experience, by revealing shifts in proteins that the body produces in response to inflammation that may persist months after… injury . It also detected blood clots and tissue injury.
“We identified common patterns in long Covid patients who had not recovered six months after acute infection,” compared to healthy patients, wrote the team, a collaboration of scientists from New York City’s Icahn School of Medicine at Mount Sinai, Switzerland, Sweden and London.
There is a tremendous need to diagnose and find effective ways to treat long Covid, a cluster of symptoms that include fatigue, migraines, brain fog and nausea.
Although its prevalence is difficult to estimate, surveys suggest that long Covid may affect 5.3% to 7.5% of people infected with the virus. The more vaccines you get, the less likely you are to get one. A recent study showed that one dose of the vaccine reduces the risk by 21%, two doses reduces the risk by 59%, and three or more doses reduces the risk by 73%.
What causes long Covid? Long after the initial infection, the immune response doesn’t stop fighting.
Experts don’t know why, but UCSF research has uncovered small pieces of the SARS-CoV-2 virus, possibly hidden in tissue, that persist long after infection. There is conflicting evidence on the effectiveness of the antiviral drug baxlovid in preventing long Covid.
Diagnostic testing and treatment for long Covid are urgently needed. Doctors currently treat the symptoms, rather than the underlying cause.
Jaime Seltzer, director of scientific and medical outreach at the advocacy group MEAction, which advocates for patients with long Covid and myalgic encephalomyelitis/chronic fatigue syndrome, said the new findings are important because the study “clarifies dysfunction, which is important for patients.” Or ME/CFS, which is caused by another viral infection.
“Secondly, they point the way to potential treatments, and even potential mechanisms” for the disease, she said.
“This paper builds on our understanding of long Covid by linking changes that occur during acute infection to long-term abnormalities in markers of blood cell function,” said Dr. Michael Peluso, an infectious diseases physician at Zuckerberg San Francisco General Hospital. Study the biological mechanisms that cause long Covid and the long-term impact of infection on health.
“It indicates a relationship between the virus, its immune effects, and changes in certain blood clotting pathways,” he said.
Although the study represents another step forward in understanding the science of long Covid, it will not immediately change the approach to diagnosing or treating the condition, Peluso said.
“We need more investment in larger studies to build on these findings, as well as clinical trials to test whether changing some of the abnormalities found here could lead to symptomatic benefit,” he said.
In the new study, scientists analyzed changes in the blood of 113 patients who either fully recovered from Covid-19 or had long-term Covid, as well as healthy people.
Specifically, they measured levels of 6,596 different proteins in study participants over the course of a year, then took blood samples again six months later and a year later. Proteins act as keys that fit into multiple locks on the surface of cells. Changes in proteins mean that cellular processes change.
The team found that patients with long Covid showed changes in the system of proteins that fight pathogens, such as viruses. Dysregulation of these proteins can contribute to the small “micro-clots” that sometimes appear in long-term coronavirus patients.
This type of dysregulation has also been seen in people with other diseases associated with persistent infections, such as chronic fatigue syndrome, Seltzer said. She said it’s the body’s way of adapting.
There are caveats. With only 113 patients, the study was relatively small. Many participants were so ill that they required hospitalization, which could have affected the results. Finally, she only studied changes within a year of injury; After three to five years, there may be different markers in the blood, Seltzer said.
These features suggest potential interventions, Wolfram Ruff of the Center for Thrombosis and Hemostasis in Germany wrote in a commentary accompanying the report. Anti-inflammatory medications may help. Anticoagulants may reduce the risk of dangerous blood clots.
“Ultimately, the hope is that some of these results can translate to the clinic, but we are still a long way from that,” Peluso said. “We need to keep up the momentum to get answers for the tens of millions of people who suffer from this disabling condition.”