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NASEM’s Long Covid Definition Report: A First Step In Helping Patients, Researchers, and Public Health

We know how this story goes – we’ve lived it, and those close to us have lived it. You go to the doctor, you share your symptoms, and 15 minutes later you leave with a referral to yet another specialist – but without a diagnosis or treatment plan. Or worse yet, with suggestions that will only lead to a crash. The lack of medical education, clear definitions, clear diagnostic criteria, and well-known ICD codes make the process of getting a diagnosis for ME/CFS, Long Covid, POTS, and other dysautonomias, and other infection-associated chronic conditions and illnesses a long and harrowing journey. 

The report just issued by the National Academies of Sciences, Engineering, and Medicine (NASEM) is an important step in shortening the path to diagnosis, improving medical education about our category of illnesses, and ensuring that data collection can begin to be streamlined – dramatically improving the quality and ease of research in our field. This will directly lead to treatments being available sooner. Solve representatives and partners participated in multiple levels of the stakeholder process that was utilized for the creation of the definition. Solve leadership, along with Long COVID Alliance coalition leaders, presented at the 2023 NASEM workshop that informed the creation of the definition. 

We applaud NASEM for their unprecedented inclusion of scientific experts and people with lived experience as equal collaborators in the process of creating the definition. Because of the input of our partners and other lived experience experts, the definition carries more credibility and instills more community trust. 

The National Academies of Sciences Engineering and Medicine (NASEM) just hosted an important online presentation: A Long Covid Definition—A Chronic, Systemic Disease State with Profound Consequences. Considering hundreds of top candidates, NASEM selected 16 top-notch clinical leaders, researchers, and community advocates (some who were patients with Long Covid and related illnesses like ME/CFS themselves) to form a committee for defining “Long Covid.” NASEM asked the committee to deeply review Long Covid research; to speak with patients with Long Covid and with families and advocates of patients; and to consult with other experts in clinical care, virology, social sciences, and public health to produce the most carefully considered definition of this term. In this online presentation, members of the committee discussed their recently completed work, which will have an enormous positive impact on how we support and treat patients with Long Covid.

Without a clear definition of Long Covid, patients, doctors, researchers, and society at large have struggled to conceptualize the disease and appreciate the size of its toll. One-third of Americans are still unsure what Long Covid is. Widespread disregard for this condition has devastated patients. One committee member told the stories of two patients who had lost jobs, had broken marriages, and broken mental health. Seeking help, these patients gave judges and administrators letters of support from Long Covid experts unequivocally diagnosing the disease. But the administrators refused to approve the patients for disability, not understanding the disease and thinking they were not really sick. Most commonly, patients with Long Covid told the committee that the number one way this definition would help was by simply helping to explain their condition to other people.

Committee members said they sincerely hope this new definition is valuable to patients, especially patients from underserved groups or underserved parts of the country. Said one participant, “Patients need to be able to understand it and see themselves in the definition because they may need to advocate for themselves or their loved ones for initial care (or continued care or recognition).”

Solve supports the new definition, and we’re hopeful about the tangible impact it could have on the lives of patients and caregivers. 

Solve Chief Scientific Officer Tim Hsiao, PhD, added “The new definition re-emphasizes the similarities among all infection-associated chronic conditions (IACCs), like Long Covid and ME/CFS, and our critical need for a common agenda to study these diseases. This work confirms the findings of another NASEM report this year (“Toward a Common Research Agenda in Infection-Associated Chronic Illnesses: Proceedings of a Workshop”). Solve understands the importance of comparative analyses for science and has been championing a common research agenda for IACCs by pioneering the Solve Together Real-World Data Platform (ST-RWD), which includes and cross-references both ME/CFS and Long Covid. Solve will continue to support research and catalyze field-wide collaborations to make breakthroughs possible for IACCs.”

 A three-part definition of “Long Covid”

The first part of the committee’s definition states, “Long Covid is an infection-associated chronic condition that occurs after SARS-CoV-2 infection and is present for at least three months as a continuous, relapsing and remitting, or progressive disease state that affects one or more organ systems.”

Second, to help people understand and recognize the experience of Long Covid, the committee lists key symptoms of the disease, including:


  •       shortness of breath
  •       cough
  •       persistent fatigue
  •       post-exertional malaise
  •       difficulty concentrating
  •       memory changes
  •       recurring headache
  •       lightheadedness
  •       fast heart rate
  •       sleep disturbance
  •       problems with taste or smell
  •       bloating
  •       constipation
  •       diarrhea

Also listed are diagnosable conditions that patients with Long Covid may have, including

  •       interstitial lung disease and hypoxemia
  •       cardiovascular disease and arrhythmias
  •       cognitive impairment
  •       mood disorders
  •       anxiety
  •       migraine
  •       stroke
  •       blood clots
  •       chronic kidney disease
  •       postural orthostatic tachycardia syndrome and other forms of dysautonomia
  •       myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)
  •       mast cell activation syndrome (MCAS)
  •       fibromyalgia
  •       connective tissue diseases
  •       hyperlipidemia
  •       diabetes
  •       autoimmune disorders

Third, the committee lists seven key features of Long Covid. Long Covid can follow asymptomatic, mild, or severe SARS-COV-2 infections that are either recognized or unrecognized as infections. Long Covid can be either continuous from the time of acute infection or delayed by weeks or months. Long Covid can affect anyone, although some people may be at greater risk than others. Long Covid can either worsen pre-existing health conditions or present as new conditions. Long Covid can be either mild or severe; it may resolve, or it can persist for months or years. We have no biomarker to prove Long Covid; instead, we must diagnose the disease for clinical reasons. And, finally, Long Covid can prevent patients from working, attending school, taking care of themselves or their families; it can have a profound emotional and physical impact on patients and their families and caregivers.

How does this definition differ from other definitions?

This definition differs from earlier definitions in important ways.

  •   Gives concrete examples of symptoms and conditions typical of Long Covid
  •  Indicates to wait three months before fully diagnosing Long Covid to maximize the sensitivity and specificity of diagnoses (e.g., to rule out      other possibilities, to allow the possibility that symptoms resolve in the short term)
  •  Requires no laboratory test to confirm SARS-CoV-2 infection because shutting out patients with Long Covid for this reason would do too much harm
  •  Acknowledges that we still lack biomarkers of this disease
  •  Strongly acknowledges unequal treatments for patients with Long Covid from underserved populations, and firmly acknowledges that Long Covid severely affects human function
  •  Uses the term created and preferred by patients themselves (“Long Covid”), not terms more common among researchers (like “post-acute COVID-19 syndrome” or “post-acute sequelae of SARS-CoV-2 infection”)
  • Establishes other key terms (“infection-associated chronic condition” and “disease state”) that will substantially advance how we relate Long Covid to other chronic illnesses

How do we use this definition?

Patients, families, caregivers, researchers, administrators, and employers will have substantial use for this definition. Patients can use this definition to get support from government agencies and doctors (especially those who may be less familiar with the disease). Families and employers can use the definition to better understand patients’ conditions and limitations. Researchers can use the definition to better understand the disease (for example, by including in clinical trials those patients who meet the criteria, but who may not have a positive COVID-19 test). And public health officials can use this definition to better track the prevalence of Long Covid and to more fairly and effectively administer funds and resources to support the millions of patients with this disease.

Final recommendations to NASEM

The committee strongly recommended that all government agencies, health care providers and organizations, researchers, employers, and patients adopt this new definition and use the term “Long Covid.” They recommended that the Office of Long Covid Research and Practice and the Long Covid Coordination Council lead domestic and international organizations in widely distributing and implementing the definition. Finally, the committee recommended that the Office of Long Covid Research and Practice should reexamine and update this definition in no more than three years from now (or sooner if important new information becomes available).

Committee members took particular care to say they believed this new definition would go a long way to change the system to better help patients. They also stressed this definition shines a much-needed spotlight on similar conditions that often coexist with Long Covid (e.g., ME/CFS, POTS, and migraine headaches). Caitlin Pedati, a committee member, pediatrician, public health director, and patient advocate, said “There is hope. We’re going to continue to address this really important public health condition. And while we may not know everything today, it doesn’t mean that there’s nothing we can do. Having this definition is a big step toward better understanding how we can treat and prevent people from suffering from this condition.”

Read the NASEM Long Covid definition report in its entirety here.

You Can Help Spread the Word About the New Long Covid Definition!

Our friends at the Covid-19 Longhauler Advocacy Project (C19LAP) have some great suggestions for how you can help support the dissemination, adoption, and implementation of the 2024 NASEM Long Covid definition. 

“A major barrier faced in Long Covid is the inability to make sense of the existing data due to the use of different definitions, terminology, and inclusion and exclusion criteria. This definition was created to be the consensus definition that all entities use, however, we need your help in getting the word out, and then consistently urging and supporting adoption and implementation of the definition through some of the following actions:


  1. Media Outreach! Make them aware of the definition and report release, what it means and can lead to, how it answers to current barriers faced, and how it would directly impact you and your family.
  2. Send it to your Members of Congress and local government officials. Urge them to implement public health policies and programs utilizing the information within the definition and report.
  3. Send it to your clinicians! Ask them to share it with their colleagues and healthcare facilities. Ask them to implement in-house training or include this information in public speaking engagements.
  4. Send this to researchers to make them aware of this update and needs in Long Covid research.
  5. Contact health agencies urging them to rapidly adopt and implement the definition.”



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