Who Is More At Risk Of Long-Term Covid?

Who Is More At Risk Of Long-Term Covid?

Researchers Are Trying To Find Which People Are More At Risk Of Developing Long-Term Symptoms Of Covid; But Since Long Covid Appears In Different Forms, It Is Difficult To Identify The Risk Factors.

For millions of people, Covid-19 does not end with a negative test. Symptoms can persist or recur weeks or months after the virus has disappeared from the nose and throat. New symptoms may appear and last for months. People with prolonged covid have symptoms for a long time, and it is still unclear who is most at risk of developing the condition.

Researchers still do not have an official definition for covid, and its symptoms are widespread. Some people experience severe fatigue that interferes with their daily life. Others who share brain fog can’t concentrate or have memory problems.

Others suffer from organ damage or persistent coughing and breathing problems. “People can have prolonged covid in different ways,” says Lera Horowitz, MD, an internist at New York University Langone Health Medical Center. “It’s not just a disease, and that’s why it’s difficult to study.”

The wide range of symptoms makes it difficult to identify people at risk for long-term health problems from the disease. Some post-Covid issues may result from an injury from the virus or the stress of being hospitalized for a severe illness. In other cases, the body’s immune response to the virus causes damage.

Alternatively, the virus may be hiding somewhere in the body (probably the gut) and causing symptoms to persist.

 Different causes may have other risk groups, says Hannah Davis, co-founder of the Patient-Led Research Collaborative.

Of course, there is evidence about who is at risk. Studies show that women are more likely to develop long-term symptoms than men. Covid patients with more than five symptoms during the first week of infection, or those who already have diseases such as asthma, are more at risk of prolonged covid.

In addition, age appears to be a risk factor, although results are inconsistent regarding whether older or middle-aged individuals are more likely to develop the condition. Populations disproportionately affected by COVID-19 (such as blacks and Hispanics) may similarly experience prolonged COVID-19 disparities. Horowitz says that while the vaccination appears to provide long-term protection against Covid-19, it’s not clear how much protection it provides.

Age is a significant risk factor for severe Covid-19, and the US Centers for Disease Control and Prevention lists more than 30 health problems, including cancer and lung disease, as risk factors. “Many researchers assume that the risk factors for long-term covid are the same, but there is no scientific basis for this,” says Davis.

In the case of prolonged covid, there are many more factors that researchers may be neglecting. Experts search for those risk factors using health records, medical examinations, and knowledge of diseases with symptoms similar to covid.

long covid / long covid

Electronic health records may hold essential clues when looking at who is at risk of prolonged Covid-19.

Horowitz is part of the US National Institutes of Health’s RECOVER initiative, which aims to understand the lasting effects of Covid-19. One branch of this study involves mining millions of electronic health record files to identify potential patterns.

\Studying millions of these records should identify potential risk factors that are rare in the general population, Horowitz says, But they may be more common in people with prolonged covid.

However, health records are not perfect, and it depends on how well doctors record information about patients who have trouble sleeping, extreme fatigue, or other complications in the database. Horowitz says these things are usually not well documented and explained, so we’re missing some factors.

Horowitz and colleagues also study thousands of people directly to account for health record flaws. Participants answer a questionnaire every three months so the team can determine what symptoms people have and whether their symptoms are improving or worsening. Then blood, urine, stool, and saliva samples can show what is happening in the body.

Testing those samples can determine whether the coronavirus is still in the body and causing problems or whether the immune system has learned to attack the body itself. Participants with abnormal test results will undergo additional testing.

 The study includes a wide range of participants: adults and children, pregnant people, people with Covid-19, and people who have died after contracting the disease.

Some of the potential risk factors the team is looking for include diseases such as autoimmune diseases and other viral infections. Meanwhile, people who have never had the virus are essential controls to highlight how different people who have had Covid are.

So far, more than 7,000 people have been enrolled in the study, and the group plans to enroll another 10,000 people. It is a massive amount of data, But preliminary results may be available soon. Hurwitz says:

We will probably try to look at that data provisionally this fall. It wasn’t easy because we deliberately wanted to enroll 18,000 people to have enough power to look at the things that mattered to us. I don’t want to cheat and look at the results too soon, But we know there is a lot of interest in it.

Striking similarities

Some symptoms of prolonged covid (such as brain fog, fatigue, and trouble sleeping) mirror another illness: myalgic encephalomyelitis/chronic fatigue syndrome, or ME/CFS. Other long-term symptoms, such as rapid heart rate and dizziness, fall under nervous system disorders called autonomic dysregulation. Davis has been suffering from prolonged covid since March 2020. He says that potential risk factors for these diseases have been largely ignored in long-term Covid research.

Among the possibilities scientists consider concerning Covid are the Epstein-Barr virus, migraine, and some autoimmune diseases. Davis said the virus had been linked to ME/CFS for decades, although the link is tenuous. The Epstein-Barr virus is a critical case, Davis says, because the infection can last a lifetime because the virus can hide in the body and reappear after a while.

There is preliminary evidence of a link between the Epstein-Barr virus and Covid-19. Several studies have shown evidence in the blood samples of some people with long-term covid that their immune systems have recently been affected by the Epstein-Barr virus. The Epstein-Barr virus can cause infectious mononucleosis, a disease characterized by severe fatigue.

Other studies have found signs of the virus itself.

In 2021, Davis and colleagues found that 40 of 580 people with prolonged Covid symptoms who responded to an online survey reported that they had recently been infected with Epstein-Barr virus or were currently infected.

Epstein-Barr virus

Researchers are investigating whether Epstein-Barr virus infection (shown in this transmission electron microscope image) may be associated with prolonged covid.

In the case of ME/CFS, another illness caused by a different virus may trigger the Epstein-Barr virus, which then causes fatigue syndrome. Due to the similarities between this disease and the long covid, some scientists wonder if the two are the same and if the coronavirus acts as their initiator.

Nancy Klimas, an immunologist at Nova Southeastern University, says that examining health conditions that increase the chance of prolonged Covid-19 could provide answers for both diseases. It is because researchers can identify people who develop long-term symptoms after an episode of Covid. However, it is challenging to identify infections that may have occurred before ME/CFS.

Also, says Klimas: “There is a big difference in these two fields, and that difference is money.”

He has received funding from the Centers for Disease Control and Prevention to compare patients with prolonged covid with those with ME/CFS. Also, the team hopes that physical examinations and specialized tests can reveal whether the two diseases are, in fact, the same illness and be a step toward understanding the mechanisms behind the persistent symptoms.

However, because long-term covid generally includes a wide range of symptoms, figuring out who is most at risk of contracting it can take time. “If Covid were just a disease that affected the lungs, the heart, or the brain, it would be easier to do research,” Horowitz says. But now we have to test everything.”