First Steps to a Clinical Definition of Long COVID

In the wake of the COVID-19 pandemic, Post Acute sequela of SARS-CoV-2 infection (PASC), or Long COVID, as it’s often called, is a growing public health concern.

NIH (USA National Institute of Health) clinicians and scientists have released a study that identifies the most penetrant symptoms of Long COVID.

Using these symptoms as a yardstick, doctors can assess more easily whether a patient would benefit from a referral to Long COVID services.

Long COVID Symptoms Assembled

A new study published in Journal of the American Medical Association presents a list of 37 symptoms strongly associated with PASC.¹

Within this set, researchers, led by Massachusetts General Hospital, identified twelve symptoms that were significantly more commonly reported in PASC patients than patients who had not contracted COVID-19. According to this study these twelve most common symptoms are:

• Abnormal movements
• Brain Fog
• Changes in libido
• Changes in ability to smell/taste
• Chest pain
• Chronic cough
• Dizziness
• Gastrointestinal symptoms
• Heart palpitations
• Malaise
• Thirst
• Hair loss

The other symptoms include

Shortness of breath; pain: abdominal, back, foot, head, joint, muscle, skin, throat; anxiety; depression; fatigue; weakness; tremors; sleep apnea; sleep disturbance; swelling of legs; bladder problems; fever/chills/sweats; vision changes; hearing changes; skin rash; skin colour changes; problems with teeth.

The researchers also noted that some symptoms tended to cluster together, hinting that there are subtypes of PASC. This could explain the wide variation in reported effects of Long COVID.

What is PASC/long COVID?

PASC is a chronic health condition that develops after infection by the SARS-CoV-2 virus.

Typically, when someone gets sick with COVID-19, they will feel better once they recover from the infection. This can take a few days or a few weeks.¹

However, some people find that their symptoms linger for a long time after the viral infection has been cleared. In some cases symptoms will go away at first but then return later.

Others will develop new, troubling symptoms long after apparently recovering. Initially people experiencing this condition called themselves “COVID long haulers”, later naming the phenomenon Long COVID, with the clinical name, PASC.

The RECOVER Initiative

The USA’s National Institute of Health has brought together a consortium of expert scientists and clinicians, the RECOVER initiative, to investigate what PASC is, how it occurs and how best to treat it.

While more than 200 symptoms have been loosely reported¹, an agreed definition of PASC is still under construction. The RECOVER study¹ involved over 9,500 people from 85 sites across the United States.

This study took an unusual approach in that they started with a blank slate. They recruited people who had been infected with the virus at different stages of the pandemic, and people who had never been infected.

They then collected the participants’ demographics and symptom information via remote surveys and office visits. Researchers collated the most frequently reported Long COVID symptoms and compared them to symptoms experienced by people who have not had COVID-19.

The 37 symptoms listed were more likely to occur in people who had experienced COVID-19 and were more severe.

Researchers could predict whether an individual had been diagnosed with PASC based on number and severity of the 37 symptoms they experienced.

An Ongoing Process

The list of symptoms is not exhaustive. Some patients may experience none of the 37 listed symptoms, and yet still have long COVID/PASC.

The study is ongoing and over time, as researchers supply more data, the significance of some symptoms might change and others may be added.

Drawbacks of this study include: the reliance on patient-reported information, not accounting for other variables that could have influenced the results, and the dynamic nature of the PASC score. Nonetheless, this study provides a starting point to a working definition for PASC, and for developing standard of care protocols.

References:

1. Thaweethai T, Jolley SE, Karlson EW, et al. Development of a Definition of Postacute Sequelae of SARS-CoV-2 Infection. JAMA. 2023;329 (22):1934–1946. doi:10.1001/jama.2023.8823
2. RECOVER. RECOVER: Researching COVID to Enhance Recovery. Accessed August 9, 2023. https://recovercovid.org/about
3. (NIH) NIoH. Long COVID. Accessed August 11, 2023. https://covid19.nih.gov/covid-19-topics/long-covid