National Academies Announces Broad New Definition of Long COVID

The new comprehensive definition of Long COVID from the National Academies of Sciences, Engineering, and Medicine (NASEM) was developed to improve consistency, documentation, and treatment for both adults and children.

by NASEM's definition of long-term coronavirus in 2024 Published on June 11, 2024, “Long COVID is an infection-associated chronic illness that occurs after SARS-CoV-2 infection and is present for at least 3 months as a continuous, relapsing-remitting, or progressive illness affecting one or more organ systems.”

People with long COVID may experience shortness of breath, rapid heart rate, extreme fatigue, fatigue after exercise, or Sleeping disorder With one or more diagnosable conditions, such as interstitial lung disease, arrhythmia, or postural orthostatic tachycardia syndrome (POTS) Myalgic encephalomyelitis/Chronic fatigue syndrome (ME/CFS), diabetes, or an autoimmune disease. The illness may worsen an existing health condition or manifest as a new health condition.

This definition does not require laboratory confirmation or other evidence of initial infection. Long COVID can occur following SARS-CoV-2 infection of any severity, including asymptomatic infection, whether or not initially recognized.

Previously, several provisional definitions and terminology for long COVID had been proposed by the World Health Organization (WHO) and the US Centers for Disease Control and Prevention, among others, but no common definition or terminology had been established.

The new definition was developed at the request of the Office of Strategic Preparedness and Response and the Office of the Under Secretary of Health (OASH) and was prepared by a multi-stakeholder committee convened by NASEM, which recommended that the new definition be universally adopted by the federal government, clinical societies and associations, public health workers, clinicians, payers, the pharmaceutical industry, and other stakeholders who use the term “long COVID.”

Recent surveys suggest that about 7% of Americans have experienced or are currently experiencing long-term symptoms of COVID-19. “That number runs into the millions,” said panel chair Harvey V. Feinberg, M.D., president of the Gordon and Betty Moore Foundation. Medscape Medical News.

Feinberg noted that the new definition “doesn't eliminate the problem of clinical judgment, but we think it has the real benefit of raising in clinicians' minds the real possibility that, in the current environment where this virus is spreading, a patient's strange symptoms are real and possibly related to a manifestation of long COVID.”

One way this new definition differs from previous definitions by WHO and others is that it “talks about diagnoses of exclusion. One of the key things about our definition is that other diagnosable conditions such as ME/CFS and POTS can be part of long COVID. They are not substitutes. In fact, they are expressions of long COVID,” he said.

In fact, the NASEM report also introduces the term infection-associated chronic conditions (IACC). This is important, Feinberg said, “because this is a larger group of conditions that includes Long COVID. This highlights the association of Long COVID with other conditions that can result from different infections. We also adopted the term 'conditions' to convey the severity and reality of this disease in patients' lives.”

Comments on the new definition

In a statement provided Medscape Medical News“Describing Long COVID as an IACC not only fulfills NASEM's goal of enabling clinicians, researchers, and public health officials to meaningfully identify and support all those who suffer from illness or disability after SARS-CoV-2 infection, but also allows for direct comparison to other known IACCs (e.g., ME/CFS, post-treatment Lyme disease, POTS) that have afflicted many people for decades,” said Lucinda Bateman, MD, and Braden Yellman, MD, co-medical directors of the Bateman Horn Center in Salt Lake City.

Feinberg pointed out another important aspect of the NASEM report: “Our definition has a clear statement about equity, explaining that Long COVID can happen to anyone, young or old, regardless of race, age, sex, gender, orientation or socioeconomic status. … This does not mean that everyone is at equal risk. There are risk factors, but the key is the universal nature of this as a disease.”

Two clinical directors of long-term COVID programs contacted Medscape Medical News The new definition was praised by Jijiang Chen, MD, director of the Post-COVID Care Center at Mount Sinai Hospital in New York, who said, “It is very similar to the definition we have been using in clinical practice since 2020. The broad definition is very helpful in including all patients who may be affected. It is also important to take children into account, as they tend to be less frequently ill and therefore typically do not receive attention. Creating a uniform definition will be helpful in both clinical practice and research.”

“I think they intentionally left the definition broad so that physicians aren't necessarily using the definition to rule individuals out, but to help them use perhaps more of a clinical gestalt to make this diagnosis… I think this definition gives clarity to health care providers of what exactly falls under the heading of a long COVID diagnosis,” said Nisha Viswanathan, MD, director of the Long COVID Program at the University of California, Los Angeles.

Viswanathan also said he hopes the definition will help patients when applying for disability pensions: “Because there was no clear definition of long COVID until now, it was very easy for disability pension providers to reject applications from patients whose symptoms persisted… We think this may actually ultimately help ensure that patients who are disabled to the point where they can't work have the ability to look after themselves.”

The report states the expectation that the definition “will evolve as new evidence emerges and our understanding of long COVID improves.” The writing committee called for a reconsideration “within three years.” Factors that could prompt a reassessment include improved testing methods, the discovery of medical factors or biomarkers that distinguish long COVID from other conditions, or new treatments.

Meanwhile, Feinberg said: Medscape Medical News“If this definition increases preparedness, awareness, openness and response to long COVID-19 patients, it will have done its job.”

Feinberg, Bateman, Yellman, Viswanathan, and Chen have no relevant disclosures..

Miriam E. Tucker is a freelance journalist based in the Washington, D.C. area. She is a regular contributor to Medscape and has published other articles. The Washington PostNPR shot I run a blog, Diatribe, and on X (formerly Twitter) I'm @MiriamETucker.