Consensus on the research definition of long COVID in children and young people will allow comparisons between studies, strengthening the evidence base on the condition

COVID-19 illustration

For the first time, in a landmark study accepted for publication in the Archives of Disease in Childhood, a formal agreement has been made on a research definition for post-acute COVID-19, or ‘long COVID’ as it is commonly known, in children and young people.

The study had a single objective—to derive a research definition for long COVID in children and young people to allow comparisons of the prevalence, course, and outcome of long COVID in this age group between research studies. According to the authors, the ‘slew of definitions’ currently used to characterise long COVID in children and young people differ in the number, type, and duration of symptoms, which hampers research efforts. This lack of consensus has contributed to a wide reported variation in the estimated prevalence of long COVID in children of 1–51%. The authors say that a ‘consistently applied definition’ of long COVID will help to reduce the variability of prevalence estimates.

Statements sequentially whittled down 

To formulate the definition, a three-phase online Delphi process was used, followed by a virtual consensus meeting. The 123 participants registered to take part in the study included 23 people (19%) in a lived experience panel, 50 (42%) in the researcher or researcher/service delivery combined panel, and 47 (39%) in the service delivery panel. Of 120 registered participants, 105 (88%) completed phase one, 86 eligible participants (82% of those completing phase 1) completed phase two, and 77 eligible participants (90% of those completing phase 2) completed phase 3. Seventeen participants attended and voted at the consensus meeting—four (23%) from the service delivery panel, 11 (65%) from the researcher panel, and two (12%) from the lived experience panel.

Presented with 49 statements in each phase, participants scored these from one to nine based on how important they perceived them to be with regard to their inclusion in the research definition of long COVID in children and young people. Having been sequentially whittled down in three phases, 10 statements were discussed at the consensus meeting, and a panel of eight 11–17 year olds affected by long COVID also reviewed the statements to reach a final agreement. Five of the statements were agreed to be included in the definition, which stated:

Long COVID in children and young people is a condition in which a child or young person has symptoms (at least one of which is a physical symptom) that:

  • have continued or developed after a diagnosis of COVID-19 (confirmed with one or more positive COVID-19 tests)
  • impact their physical, mental, or social wellbeing
  • are interfering with some aspect of daily living (for example, school, work, home, or relationships), and
  • persist for a minimum duration of 12 weeks after initial testing for COVID-19 (even if symptoms have waxed and waned over that period).

Dr David Strain, Chair of the BMA Board of Science and Clinical Senior Lecturer and Honorary Consultant at the University of Exeter Medical School, told the Science Media Centre: ‘A Delphi study builds a consensus from the world’s experts by presenting a series of statements and continuing to refine them until there is agreement as to what the definition of paediatric long COVID should be.’ He added: ‘This is vitally important in order to align the global research effort into long COVID.’

Reassuringly similar 

From the five agreed statements, a further research definition was proposed to align with the World Health Organization (WHO) definition for adults: ‘Post-COVID-19 condition occurs in young people with a history of confirmed SARS CoV-2 infection, with at least one persisting physical symptom for a minimum duration of 12 weeks after initial testing that cannot be explained by an alternative diagnosis. The symptoms have an impact on everyday functioning, may continue or develop after COVID-19 infection, and may fluctuate or relapse over time.’

The authors concluded: ‘This is the first research definition of long COVID (post-COVID-19 condition) in children and young people, and complements the clinical case definition in adults proposed by WHO’, adding that the two definitions are ‘reassuringly similar’.

They reiterated how widespread adoption of this definition would allow comparisons between studies such that a core outcome set can be developed and the prevalence, course, and outcome of long COVID in children and young people reliably evaluated, which ‘will substantially help strengthen the evidence base on this debilitating condition’.

In addition, the authors said that a consistently applied definition of long COVID will help to provide a ‘more accurate picture [of] the true impact of the condition’.

The researchers emphasised the need to differentiate between a clinical case definition and a research definition of long COVID, and explained: ‘It is understandable that the patient groups representing people with long COVID are concerned about a definition that could restrict access to services that are needed.’  They went on to say that, in their view, decisions about whether a child or young person can see a healthcare professional, access any support needed, or be referred, investigated, or treated for long COVID should be a ‘shared decision involving the young person, their carers, and clinicians’

Dr Strain reiterated that it was important that the definition was a research one and not a clinical one, highlighting that the 12-week period in the research definition ‘does not necessarily mean that a child or young person should need to wait 3 months before being offered help or assistance from their healthcare team; indeed, a 3-month delay in offering support to a child or young person, at this vitally important period of their educational development, could have lasting long-term impacts.’

This article originally appeared on Medscape, part of the Medscape Professional Network.


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