Long COVID finally gets a universal definition

The new description includes more than 200 symptoms and doesn’t put limits on when they start

In this illustration, a woman stands slightly knockkneed, holding her hands by either side of her face, while a giant red coronavirus with yellow bulbous projections hovers right over her head.

Long COVID affects millions of Americans of almost all ages, but there has been no standard definition for the condition until now.

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A sweeping new definition of long COVID could help affected people get recognition of their condition and improve diagnosis and treatment.

The U.S. National Academies of Sciences, Engineering and Medicine announced the definition for long COVID June 11.

Previous definitions of long COVID have been all over the map, each with its own set of accepted symptoms, timelines and requirements for proof of infection (SN: 7/29/22).

That lack of standardization “left many patients in the lurch without clear ability to be recognized for the condition that they had, with difficulty explaining to family and even to their caregivers,” says Harvey Fineberg, a public health expert who chaired the committee that drafted the definition. “We heard from literally hundreds of people experiencing long COVID about the challenges that they had in being heard, in gaining access to care and obtaining the care they needed.”

More than 1,300 people contributed to the definition. The committee decided to adopt the patients’ own term “long COVID” instead of more medical terms such as “post-acute sequelae of COVID-19” that have also been used to describe the long-term condition.

Adoption of the name the patients advocated for gives validation to everyone with the condition who has been struggling, sometimes for years, to have their experience acknowledged, says Daria Oller, a physical therapist in New Jersey who developed long COVID in 2020. “Now, people are trying to not use the term long COVID, and all of us, patients from the first wave, are fighting. We were ignored. That’s ours. We named it.”

The committee chose to go with the name because it’s simple, familiar and easy to communicate, Fineberg said during a webinar introducing the definition. 

No one knows exactly how many people have long COVID, but a recent survey found that more than 17 percent of adults in the United States have experienced the condition. While the National Academies don’t have regulatory or legal power to enforce adoption of the definition, the respected body of scientific experts’ recommendations are often used in making regulatory decisions, determining medical and scientific policies and crafting laws.

Here’s what to know about the long COVID definition.

What is long COVID?

It’s a medical condition that belongs to a family of chronic conditions that kick in after infections with viruses, bacteria, fungi or parasites. That includes chronic health problems such as myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and Lyme-associated chronic illnesses.

According to the National Academies’ definition, long COVID is a medical condition that persists for at least three months after an infection with SARS-CoV-2, the coronavirus that causes COVID-19. Long COVID can affect any organ or system in the body. People may have any of more than 200 symptoms, which may include difficulty breathing, brain fog, blood clots, dizziness, extreme fatigue after exercising, loss of taste or smell, fast heart rate, diarrhea, constipation, diabetes and autoimmune diseases such as lupus (SN: 2/2/22; SN: 8/21/23; SN: 1/4/22). Those symptoms can appear alone or in multiple combinations, can be continuous, get progressively worse or have bouts in which the patient gets better and then worse again.

Chronic symptoms can affect people who originally had mild to severe COVID and can even strike people who didn’t have any symptoms at all from their original infection. For that reason, the committee that crafted the Academies’ definition says that people don’t need to have had a positive COVID test to be diagnosed with long COVID.

The photo shows a person's hands holding the bits and pieces of a home COVID test, including the swab and the test strip. No results have shown up yet.
Having a positive COVID test isn’t necessary to get diagnosed with long COVID, the U.S. National Academies of Sciences, Engineering and Medicine say. A broad new definition of long COVID includes people who are experiencing chronic health issues but had asymptomatic infections, couldn’t get COVID tests or had false negative results.Fly View Productions/Getty Images Plus

The condition can strike adults and children and can start weeks or months after seeming recovery from the initial infection. The committee didn’t put an upper limit on how long after getting the original illness that long COVID could start.

There are no blood tests or biomarkers that doctors can use to reliably diagnose long COVID right now. The report calls for continued research to find such diagnostic tools.

This definition follows a June 5 report that the Social Security Administration asked the National Academies to prepare. That report similarly found that long COVID can have debilitating symptoms that can affect people’s physical function, quality of life and their ability to work or perform in school for years.

Why is the definition so broad?

The definition is “intentionally inclusive,” the committee says.

“We wanted to be sure that long COVID was not regarded as a diagnosis of exclusion,” says Fineberg, who is president of the Gordon and Betty Moore Foundation, based in Palo Alto, Calif. Everyone with lingering effects from a coronavirus infection should fall under the broad umbrella erected by the new definition. That means some people who have long-term health problems caused by a different infectious disease or other cause might be mistakenly diagnosed with long COVID, Fineberg admits.

That big-tent approach is essential for health equity, says committee member Monica Verduzco-Gutierrez, a physical medicine and rehabilitation physician at the University of Texas Health Science Center at San Antonio. The committee wanted to make sure that people who don’t have access to testing — because tests weren’t available early on and free testing has ended now — or who got a false negative test or had asymptomatic infections could still be included in the definition. 

“I think they got it right in the sense that they didn’t leave anybody out,” says Ziyad Al-Aly, head of research at the VA Saint Louis Health Care System. Al-Aly was one of the independent experts who reviewed the report.

Will the definition change?

Yes. The report calls for revision of the definition in no more than three years and possibly sooner if new science warrants it.

“We’re very mindful that the definition is only good as far as science can take us at this time,” Fineberg says.

What will the definition mean for the health care for people with long COVID?

Having “the gravitas of the National Academy of Medicine behind” the definition “will be seen by patients and patients advocates as legitimizing the illness which they have been complaining about,” says Al-Aly. “There’s a lot of gaslighting by physicians and by providers, and by the community [and] our society at large.”

Some people have dismissed the condition as being a mental health disorder, but plenty of research has established that there are widespread biological changes, Verduzco-Gutierrez says. The definition “makes it clear that long COVID is a physical health condition.”

Not requiring a positive test to be diagnosed with long COVID “is huge” for Oller, who has no proof that she was infected with SARS-CoV-2 in early 2020. “We couldn’t get tested. There were long lines, and you needed symptoms that I didn’t have.”

Before COVID, Oller was a runner and dancer. After, she had difficulty breathing and pains in her chest, which she now thinks may have been caused by microclots in her lungs. She’s had a battery of health problems that have persisted. Though many symptoms have improved, they haven’t all gone away, and Oller has accepted that she may be dealing some unwanted aftereffects of COVID-19 for life. Early on, she had no name for what she was experiencing and encountered much skepticism that anything was actually wrong with her, even from other medical professionals.

Oller is a founding member of long COVID Physio, an international peer group of people with long COVID and their allies. She was not involved in the National Academies’ report but welcomes the broad definition.

It will be something patients can take to their doctors to bolster their claims, Oller says. She understands some of the difficulties clinicians have with diagnosing long COVID. “It’s hard because it challenges a lot of our biases,” she says. “Exercise makes us worse, trying harder makes us worse. … It’s easier to blame the patient and be like, ‘Oh, you’re not trying. You’re lazy. You just want to get on disability. It’s in your head.’ It’s easier to just send them on that route than to read through all the literature.”

Over time, Oller says, the definition may be refined to include subtypes of long COVID, much the way cancer is an overarching definition of runaway cell growth but is divided by where the cancer occurs and the mutations that cause it. But for now, she says, starting out broad will allow people whose symptoms don’t “fit into a nice little package” to have their condition recognized and acknowledged.

Tina Hesman Saey is the senior staff writer and reports on molecular biology. She has a Ph.D. in molecular genetics from Washington University in St. Louis and a master’s degree in science journalism from Boston University.

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