Researchers have developed new definitions for what long COVID is and the key effects in children.
This will help harmonise research and improve understanding of the condition.
The non-hospitalised children and young people with long COVID (CLoCk) study is funded by UK Research and Innovation and the National Institute for Health Research (NIHR).
The study has for the first time defined long COVID in children.
Working with patients and carers
The research group worked with patients and carers to develop their definitions, using a democratic technique called the Delphi consensus process.
This process involves whittling down statements through several rounds of discussion, with the opinions of every participant accorded equal importance.
The new definition will ensure that research is directed towards elements of long COVID that are most important to patients.
It will help researchers to reliably compare and evaluate studies on prevalence, disease course and outcomes, providing a more accurate picture on the true impact of long COVID.
Defining long COVID in children
The CLoCk researchers scored 49 statements on long COVID by working with a panel of more than 100:
- researchers
- experts in health service delivery
- children with long COVID and their parents.
These statements were then reviewed by a panel of eight 11 to 17 year olds affected by long COVID to reach final agreement.
Their definition of long COVID 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 tests)
- impact their physical, mental or social wellbeing
- are interfering with some aspect of daily living (for example, school, work, home or relationships)
- persist for a minimum duration of 12 weeks after initial testing for COVID-19 (even if symptoms have waxed and waned over that period).
The definition, published in the journal of Archives of Disease in Childhood, closely complements the World Health Organization definition for long COVID in adults.
Reducing variability
Professor Sir Terence Stephenson, at UCL Great Ormond Street Institute of Child Health, said:
This research definition will allow us to compare research from different countries and will reduce the variability in prevalence estimates of long COVID.
The researchers emphasise the need to differentiate between a clinical case definition and a research definition of long COVID.
Professor Stephenson said:
It is understandable that the patient groups representing people with long COVID are concerned that a definition could restrict access to services.
In our view, the decision 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.
Quantitative data
The process of arriving at this definition also took into account quantitative data from the CLoCk study, an innovation within the Delphi approach process.
This data has now been published as a peer reviewed paper in Lancet Child and Adolescent Health.
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