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Pastor Ben Thomas, who got COVID-19 early at the start of the pandemic and is still experiencing breathing and heart problems two years later, is pictured at his home in East Meadow, New York on March 2, 2022. Newsday LLC/Getty Images
  • Long COVID is associated with various symptoms that continue to baffle scientists.
  • Together with people experiencing long COVID, researchers developed a questionnaire to more clearly define the condition.
  • The questionnaire will be combined with other data to provide physicians with a more actionable understanding of long COVID.

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While “long COVID” is a familiar term and a concerning phenomenon, it is still unclear what the condition is. Also called post-COVID-19 syndrome, long COVID encompasses lingering symptoms of COVID-19, as well as symptoms that appear after COVID-19’s acute or active infection stage. It may involve any number of organs.

Now, researchers from the University of Birmingham’s Centre for Patient-Reported Outcomes Research in the U.K. have developed and validated a comprehensive questionnaire designed to help pin down a definition of long COVID.

Dr. Jai G. Marathe, infectious disease expert at Boston Medical Center in Massachusetts, described the problem to Medical News Today:

“Long COVID is a condition that the clinicians are learning along with patients, and in a lot of cases, we are learning from patients. Post-COVID conditions may look different for different people, as over 50 symptoms have been described, and often it is difficult to recognize by both the patients and the medical community.”

“Now,” said Dr. Marathe, “add to this the fact that an estimated 30% of COVID survivors may experience long COVID, and the sheer number of presentations that different patients may exhibit becomes staggering. In addition, the intensity of symptoms may range from very mild with minimal impact on day-to-day life to severe, resulting in disability.”

“Think of [long COVID] as boarding a running train where the departure and destination stations are unknown and the answer to the ever-dreaded question, ‘Are we there yet?’ is a big mystery.”
— Dr. Jai G. Marathe

A study describing the creation of the Symptom Burden Questionnaire for long COVID, or SBQ-LC, is published by the bmj.

The lead author of the study and questionnaire is Dr. Sarah Hughes, a research fellow at the University of Birmingham. She shared her team’s motivation with MNT:

“We know that long COVID covers a wide range of, often fluctuating, symptoms that can appear at any time following the initial COVID-19 infection. This makes it difficult to know what long COVID actually is and therefore what should be measured.”

“What was clear was that individuals living with long COVID told us that existing measures did not fully capture their lived experience.”
— Dr. Sarah Hughes

To gain a more useful understanding, the researchers designed a “patient-reported outcome measure,” or PROM. People who have had COVID-19 can complete it themselves or in an interview.

From these interviews and literature reviews, the researchers identified a set of long COVID symptoms. They presented the results to 10 clinicians who validated and identified the symptoms of clinical concern. They then field-tested the draft questionnaire on 274 adults with long COVID.

Dr. Hughes further explained:

“When deciding ‘what to measure’ in long COVID, our decisions were based on current understanding of long COVID from the published literature, identification of symptoms of clinical concern from a health practitioner and researcher perspective, but most importantly, first-hand accounts of symptoms as experienced by people with long COVID.”

The researchers “worked extensively with individuals with lived experience at each phase of the SBQ-LC’s development to ensure the items (questions) represented all the symptoms of long COVID considered important to individuals living with the condition,” she said.

It is impossible to know at this juncture if long COVID is a single illness or if it includes multiple conditions joined only by their origin with COVID-19.

“There is definitely value in exploring long COVID as a single condition. In the clinical setting, lumping together symptoms that can temporally be associated with COVID-19 will allow for easier identification and diagnosis of patients who will benefit from clinical evaluation and management as needed,” said Dr. Marathe.

“I would consider the investigation of long COVID a starting point for subsequent, more granular research,” she added.

An immediate consequence of the SBQ-LC will be its delivery of data to another study, the Therapies for Long COVID (TLC) in non-hospitalized individuals funded by the U.K.’s NIHR and UKRI. SBQ-LC data will be combined with that from other “PROMs (delivered through a digital platform developed by Aparito Ltd.), wearable data, and blood and other biological tests to characterize and immunologically phenotype long COVID syndromes,” according to Dr. Hughes.

“We hope,” noted Dr. Hughes, “[the SBQ-LC] will be widely adopted as part of a core outcome set for long COVID to enable comparative global data.”

Still many unknowns

Given that experts do not yet know how long after acute infection it might be before long COVID symptoms stop appearing, it raises the question of how experts can be sure that they have captured enough data to fully encompass all aspects of the condition.

“I think this is a very difficult question to answer, precisely because we do not know who is likely to develop long COVID. Will new emerging variants impact the development of long COVID, and how long it will take for the post-COVID condition to resolve for each patient?” said Dr. Marathe.

She pointed out that this kind of uncertainty has been experienced before, citing the long-term Framingham Heart Study:

“As our understanding of heart disease grew, the research results were no longer referred to as preliminary, and I think the same will happen with long COVID data.”