New Long COVID Definition Proposed by National Academies

— Committee urges adoption, says it will aid in consistent diagnosis, documentation, and treatment

MedicalToday
A computer rendering of COVID viruses in front of the U.S. flag.

A from the National Academies of Sciences, Engineering, and Medicine (NASEM) offers a new definition of long COVID in an effort to streamline the diagnosis and treatment of the condition, which has serious medical, social, and economic consequences for patients, according to the authoring committee.

Long COVID should now be defined as an infection-related chronic condition that occurs after COVID-19 and remains present for at least 3 months "as a continuous, relapsing and remitting, or progressive disease state that affects one or more organ systems," the committee wrote. The definition does not require laboratory confirmation or other proof of initial infection.

The committee developed the report with input from more than 1,300 participants from a range of interdisciplinary specialties, as well as patients. It was initiated at the request of the Administration for Strategic Preparedness and Response and the Office of the Assistant Secretary for Health (OASH).

"Despite the fact that there have been many efforts to characterize this condition and many different definitions put forward, there has not yet been a common definition that has been widely agreed upon," said Committee Chair Harvey Fineberg, MD, PhD, president of the Gordon and Betty Moore Foundation, during a briefing.

For example, the CDC has its own , as does OASH and the NIH, and the World Health Organization has separate criteria for and .

"The lack of a considered uniform definition that's widely accepted hampers individual patients' ability to get the care they need," he added. "It hampers research, surveillance, and the availability of support for our patients who have this condition."

Fineberg explained that one notable distinction from previous definitions is a more clear path to diagnosis for patients, which means that clinicians don't have to wait for a diagnosis of exclusion to begin treating their patients.

He said the committee wants this new definition of long COVID to quickly be adopted by all federal, state, and local government authorities, as well as clinicians, medical societies and organizations, public health practitioners, employers, and educators. Specifically, the committee highlighted the importance for several government agencies -- such as HHS, the NIH, CDC, and the Social Security Administration -- to begin using this new definition to improve research and services for patients with long COVID.

NASEM last week focused on the long-term effects of COVID-19, and potential disability benefits for patients with long COVID.

The committee said that its new definition can be applied to many purposes, including clinical care and diagnosis; eligibility for health services, insurance coverage, disability benefits, and school or workplace accommodations; public health; social services; policymaking; epidemiology and surveillance; private and public research; and public awareness and education, especially for patients and their families and caregivers.

"We believe this definition deserves wide dissemination and implementation," Fineberg said. "It is important also to monitor how well the definition works in practice: what problems emerge, how well it can be utilized both nationally and in promoting understanding globally about the role and relevance of long COVID in the lives of patients."

In addition to the new definition, Fineberg and the committee noted that their report strongly encourages all researchers, policymakers, and clinicians to use long COVID as the preferred name for this diagnosis.

Furthermore, the committee emphasized that long COVID can manifest in many ways and can involve any organ system. For example, patients can experience one or more of the following symptoms: shortness of breath, coughing, persistent fatigue, post-exercise malaise, difficulty concentrating, memory changes, recurring headache, lightheadedness, fast heart rate, sleep disturbances, problems with taste or smell, bloating, constipation, and diarrhea. However, the definition does not list any specific symptoms as being associated with long COVID as "studies estimate the prevalence of over 200 symptoms in multiple organ systems," according to the report.

The report also explained that long COVID patients can present with one or multiple diagnosed conditions, including hypoxemia, cardiovascular disease, cognitive impairment, mood disorders, postural orthostatic tachycardia syndrome (POTS), myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and autoimmune disorders such as lupus, rheumatoid arthritis, or Sjögren's syndrome.

During the briefing, committee members pointed out that including these conditions in the overall definition is not a suggestion that there is a causal association between any specific diagnosis and long COVID.

In addition to other conditions that might signal long COVID, the committee noted several important features of the condition that clinicians can use to make a diagnosis.

First, the condition can follow asymptomatic, mild, or severe SARS-CoV-2 infection, so previous infections may be unknown to patients and their healthcare providers. It is also possible for long COVID symptoms to be continuous from the initial infection or delayed for several weeks or months, according to the report.

Long COVID can affect any individual regardless of age or other demographics. It can also be exacerbated by pre-existing conditions. The committee said long COVID can be diagnosed on clinical grounds and that no biomarkers currently exist.

Ultimately, the report emphasized that long COVID is a condition that can have a profound impact on a person's life, including limiting their involvement in everyday work, educational, family, or personal activities.

"The committee strove to put forward a definition that would have a number of qualities -- precision, feasibility, acceptability, accessibility -- one that would balance benefits and harms, one that would recognize the impact on health equity, and understood unintended consequences," Fineberg said.

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    Michael DePeau-Wilson is a reporter on ’s enterprise & investigative team. He covers psychiatry, long covid, and infectious diseases, among other relevant U.S. clinical news.