Who is most at risk of long-term COVID-19 infection? It’s complicated

For millions of people, COVID-19 does not end with a negative test. Weeks or months after the effects of the virus from the nose and throat are gone, symptoms can persist or return. New messages may appear and remain for months. People who have had COVID for a long time remain unwilling to have it for a long time – and it remains unclear who is most at risk of contracting the condition.

Researchers do not yet have a file The official definition of COVID is longand its symptoms are extensive (SN: 7/29/22). Some people experience extreme fatigue that interferes with their daily lives. Others can’t concentrate or have trouble memory amid a thick brain fog. Still others have organ damage or a persistent cough and difficulty breathing.

“There are a variety of different ways people can contract COVID for a long time. It’s not the only thing,” says Leora Horowitz, MD, an internal medicine physician at NYU Langone Health. “That’s what makes the study so challenging.”

This spectrum of symptoms makes identifying people at high risk of developing long-term health problems from the disease especially difficult. Some post-COVID cases may result from damage caused by the virus or from the stress of being hospitalized with severe illness. In other cases, the body’s immune response to the virus can cause damage. Or the virus may be hiding somewhere in the body, Maybe the gutwhich helps symptoms persist (SN: 11/24/20). Different causes may have different risk groups, says Hannah Davis, co-founder of the Patient-Led Research Collaborative, a research and advocacy group that has been studying COVID for a long time.

There are some general hints about people at risk. Studies indicate that Women are more likely than men to develop long-term symptoms. covid-19 infected patients More than five symptoms in the first week of infection or Pre-existing health conditions such as asthma You may be more susceptible to contracting COVID for a long time. Age also appears to be a risk factor, although results are mixed regarding Whether the burden falls on the elderly or middle-aged people. Populations that have been disproportionately infected with COVID-19 in general—including black and Hispanic people—may experience similar disparities with prolonged COVID-19. Horowitz says that while vaccination appears to protect people from infection with the COVID virus for a long time, it remains unclear how much.

Age is a risk factor for severe COVID-19, lists the US Centers for Disease Control and Prevention More than 30 health problems, including cancer and lung disease, which also increase the risk. “A lot of researchers assume that these [risk factors] “It’s going to be the same for Covid for a long time and there’s no scientific basis for that,” Davis says. There’s a lot researchers may be missing out on when it comes to the long COVID.

Using health records and exams, and knowledge of diseases with prolonged COVID-like symptoms, experts are looking for these risk factors.

health check

When it comes to better handling of people at long-term risk of contracting the COVID virus — which also refers to the shaky nickname after severe consequences of SARS-CoV-2 infection — electronic health records may hold important clues.

Horowitz is part of the RECOVER initiative of the US National Institutes of Health It aims to understand the long-term effects from COVID-19. One arm of the study involves digging through millions of electronic health records to find potential patterns.

Horowitz says studying millions of these records should identify potential risk factors that are rare in the general population but possibly more common for people who have had COVID for a long time. “This is difficult even in a cohort study of thousands.”

But health records aren’t perfect: they depend on doctors recording that patients have trouble sleeping or concentrating, or are tired. “The things people complain about, we’re really bad at writing these diagnoses in the logs,” Horowitz says. “So we miss that.”

To explain deficiencies in health records, Horowitz and colleagues also study thousands of people firsthand. Participants answer a questionnaire every three months so that the team can determine what types of symptoms people are experiencing and whether they are getting better or worse.

Then blood, urine, stool, and saliva samples can reveal what’s going on in the body. Tests on those samples can reveal whether the coronavirus is still present and causing problems, or whether the immune system has learned to attack the body itself. Participants with abnormal test results will undergo additional purposeful tests.

“Unlike the electronic health records where they’ve been hit or lost, like someone may or may not have had a CAT scan, we’re saying here, ‘OK, you have trouble breathing. We’ll take a look at your lungs,'” Horowitz says.

The study includes a group of participants: adults and children, pregnant women, those currently infected with COVID-19 and people who died after contracting the disease.

Some of the potential risk factors the team looks for include autoimmune diseases and other viral infections. The list may increase as more people join the study. “We try to balance fishing and make sure we at least catch things that could be in the water,” Horowitz says.

Among the short supply, though, are people who have never contracted the virus — important “controls” to highlight the difference in people who have contracted COVID-19.

So far, more than 7,000 people have signed up, and the group plans to recruit about 10,000 more. There is a lot of data, but preliminary results may start coming in soon.

“We’ll probably try to get an interim peek at this data this fall,” Horowitz says. “It’s tough because we intentionally wanted 18,000 people to sign up so we had enough strength to really look at the things we care about. I don’t want to cheat and search too early, but we also know there’s a lot of interest.”

Amazing similarity

Some of the prolonged symptoms of COVID — brain fog, fatigue, and difficulty sleeping — reflect another disease: myelitis encephalomyelitis/chronic fatigue syndrome, or ME/CFS. Other prolonged symptoms of COVID, such as rapid heartbeat and dizziness, fall into the category of nervous system disorders called dystonia. Similar symptoms may contrast with similar risk factors.

However, potential risk factors for these conditions are largely missing from the long-running COVID research, says Davis, who has struggled with COVID for a long time since March 2020. Among the possibilities scientists are considering are things like Epstein-Barr virus, migraines, and some immune diseases. subjectivity.

The Epstein-Barr virus could be big, Davis says. The infection lasts for life because the virus can hide in the body and may reappear. This virus has been associated with ME/CFS for decades, Davis says, although the connection is poor.

Black and white view of Epstein-Barr virus under a scanning electron microscope
Researchers are exploring whether Epstein-Barr virus infection (shown in transmission electron microscopy image) may be linked to prolonged COVID-19.Dr. Fred Murphy / CDC

There are already some early hints of a link between the Epstein-Barr virus and the long-term COVID. Multiple studies have found evidence in blood samples from some long-time COVID patients The immune system recently fought off the Epstein-Barr virus, which can cause infectious mononucleosis, a disease characterized by extreme fatigue. Her other studies I found signs of the virus itself. And in 2021, Davis and colleagues found that 40 out of 580 people with prolonged COVID symptoms who responded to an online survey reported that they Current or recent Epstein-Barr virus infection.

With ME/CFS, it is possible for another disease caused by a different virus to cause the Epstein-Barr virus, which then causes fatigue syndrome. Given the similarities between this case and the long-running COVID, some scientists are questioning whether the two are in fact the same disease, with the coronavirus now known as the only trigger.

Studying the health conditions that increase chances of contracting Covid for a long time can provide answers to both diseases, says Nancy Klimas, an immunologist at Nova Southeastern University in Fort Lauderdale, Florida. This is partly because researchers can more easily identify people who have developed long-term symptoms after a bout of COVID-19 compared to unknown infections that may precede ME/CFS.

Klimas also says, “There’s a big difference in these two areas and that’s money.” It now has funding from the CDC to compare long-time COVID patients with people who have ME/CFS. The team hopes that physical examinations and specialized tests will reveal whether the two diseases are indeed the same and be a step toward understanding the mechanisms behind the chronic symptoms.

However, since the prolonged COVID as a whole includes such a wide range of symptoms, it will take time to detect those at risk.

If COVID-19 is just one disease affecting the lungs, heart or brain, the research may be easier, Horowitz says. “But we have to test everything.”

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