BY JOSEPH CHOI – The Hill
COVID-19 cases are rising again — and some of them could lead to the condition known as long COVID, which brings with it myriad symptoms that can severely impact a patient’s life.
Research on long COVID remains thin, and as a result its prevalence, definition and treatment is uncertain. Signs of the condition can range of mild to debilitating, with symptoms lasting for months or even more than a year.
The National Institutes of Health (NIH) is aiming to conduct more research into the condition this summer as part of its nationwide initiative to better understand it.
Here are five things we do know about long COVID, despite the scarce definitive data.
People with asymptomatic cases can develop long COVID, too
Patients who developed severe cases of COVID-19 or had to be hospitalized are generally believed to be more likely to have long-lasting symptoms after recovering from their initial infection.
However, studies have indicated that a notable percentage of asymptomatic COVID-19 cases lead to long COVID.
One study from the FAIR Health nonprofit found that nearly 1 out of 5 people who did not experience symptoms when they initially contracted the coronavirus reported having at least one long COVID symptom about a month after their infection.
The most common symptoms observed in this study were pain, breathing difficulties, fatigue, hypertension and hyperlipidemia — which is the presence of too many lipids in the blood.
Some predisposing factors have been identified
While more research is needed, recent studies have indicated there are some conditions or factors that may predispose an individual to being more likely to develop long COVID.
Research results published earlier this year indicated that people with Type 2 diabetes, individuals with reactivated Epstein-Barr virus in their blood and those who have autoantibodies in their system are more likely to experience long COVID symptoms.
The Epstein-Barr virus is a common pathogen that many people contract during childhood. It usually remains in the body in an inactive form but can be reactivated.
Autoantibodies are antibodies produced by the immune system that attack an individual’s own healthy tissue. Many autoimmune disorders are caused by autoantibodies, and more than 32 million people in the U.S. are believed to have autoantibodies, according to the NIH.
Researchers say it is wrong to conclude that long COVID just hits sickly people. It is also occurring in healthy individuals with no preexisting conditions who had asymptomatic cases.
The prevalence of long COVID is still being determined
How many people get long COVID? Due to the current lack of extensive research, it’s not clear.
Early studies estimated that a minority of between 10 to 30 percent of COVID survivors would develop long-term symptoms. Some later studies indicated that a majority of patients — nearly 2 out of 3 — would experience long COVID.
The NIH has noted that one factor making it difficult to identify the rate at which long COVID occurs is that its wide variety of symptoms can often resemble other conditions and diseases. Long COVID cannot be tested for.
The time frame of long COVID is also still being deliberated, which affects the rates that are reported.
While some health officials consider a patient to be COVID long-haulers if they still have symptoms three to six weeks after infection, other researchers have considered the condition to be more extended, looking at individuals experiencing symptoms roughly six months after their initial infection.
Long COVID can be considered a disability in some cases
According to guidance from the Equal Employment Opportunity Commission (EEOC), people who have COVID or have previously been diagnosed with the coronavirus can be considered disabled under federal civil rights law if the symptoms cause “physical or mental” impairment that limits major life activities.
Whether or not someone can be considered disabled due to being infected with COVID-19 should be taken on a “case-by-case” basis, the EEOC said when it updated its guidance.
While the usual symptoms are fatigue, breathing issues and brain fog, other symptoms have had debilitating effects on long-haulers.
One British study found that people who had COVID cases severe enough to warrant critical care experienced the equivalent of 20 years of cognitive aging. The participants in the study were infected about six months beforehand on average and scored significantly lower in cognitive tests when compared to the general population.
COVID-19 antivirals may be a potential treatment for long COVID
Jim Heath, a researcher leading a consortium on long COVID for the NIH’s research initiative, told The Hill that antivirals would “almost surely” help with long COVID.
Heath noted that most evidence of antivirals helping long COVID is anecdotal, with the drugs having only been authorized for use in December of last year.
“So it’s a little early to tell, but we know that viral load in the blood of these viruses is important for long COVID and that disease severity does play a role,” Heath said. “Unless two plus two doesn’t equal four, you would expect that those are actually reasonable treatments for at least a set of patients.”
However, Heath noted that long COVID presents itself in a wide variety of symptoms and the antivirals likely wouldn’t help everybody with the condition.
Some research has come out to support Heath’s view.
A small, preprint study conducted by researchers from the University of California, San Francisco found that long COVID symptoms were lessened in participants who took Pfizer’s Paxlovid several weeks after testing positive for the coronavirus.
However, using antivirals like Paxlovid or Merck and Ridgeback’s Molnupiravir to treat long COVID would technically be off-label use. Coronavirus antivirals are meant to be administered within days of symptom onset, according to the Food and Drug Administration’s emergency use authorization.
This article originally appeared on The Hill.