Scientists and medical experts from around the world have agreed on a research definition for “long COVID” in children, according to a U.K.-based study, the first such consensus for young people.
The peer-reviewed paper, published in BMJ’s Archives of Disease in Childhood journal, defines long COVID, or post-COVID-19 condition, as an illness that “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.”
There are more than 200 symptoms associated with Long COVID in adults, researchers said, but the most common symptoms in both adults and children are similar, especially fatigue and headache. But less is known about long COVID in children. There are also differences including early data that suggested a higher proportion of younger patients were asymptomatic at the time of their initial infection, making a separate definition useful, researchers said.
“It is currently unclear whether long COVID represents one or many different conditions and it has consequently been difficult to derive a universally accepted definition for the condition,” the authors wrote.
“Research into the prevalence and impact of long COVID has consequently been hampered, thereby delaying the implementation of policies and services that could help affected [children and young people].”
The definition was agreed upon by a panel of participants with relevant expertise, knowledge and lived experience. Among those invited to participate, a total of 120 people registered. In addition, children between the ages of 11 and 17 were also included in the final review.
The definition aligns closely with the clinical case definition proposed for adults by the World Health Organization (WHO), and if widely adopted, could help researchers get a more accurate account of the condition and its impact on patients, the study’s authors say.
The WHO defines long COVID in adults as “people with a history of probable or confirmed SARS CoV-2 infection, usually three months from the onset of COVID-19, with symptoms that last for at least two months and cannot be explained by alternative diagnoses.”
With no formal definition for children who have post-COVID-19 condition – the preferred term by the WHO – comparison and evaluation of different studies is challenging. Definitions vary in terms of the number, type and duration of symptoms, resulting in estimates between one per cent and 51 per cent in terms of how common long COVID is in children, researchers said.
In order to reach a consensus, panel participants had to give a score between one and nine on 49 statements related to long COVID. A score of one to three meant the statement was not important, while a score of four to six meant it was important. A score of seven to nine meant it was very important.
The statements were developed based on existing literature, guidelines by the U.K.’s National Institute for Health and Care Excellence (NICE) on managing the effects of long COVID, COVID-19 advice by the U.K.’s National Health Service (NHS), and other sources. They were then pruned down in three phases with 10 final statements discussed in a consensus meeting and finalized down to five. The final statements were also reviewed by a group of eight children aged eleven to 17 to make sure their voices were heard as well.
The final statements included defining the condition as having:
• impacted a patient’s physical, mental, or social wellbeing
• interfered with some aspect of their daily living, such as school, work, home life, or relationships
• lasted for at least 12 weeks after testing positive for COVID-19, even if symptoms “waxed and waned” over that period
The authors noted some limitations and caveats to the study, including the fact that it was conducted in English. The authors noted that having representation from non-English speaking countries and less developed countries would have been preferred since the goal of the study was to provide a definition that would allow comparison between studies from around the world.
Researchers also highlighted the importance of distinguishing between their research definition and a clinical case definition.
“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,” researchers said.
“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 [care givers] and clinicians.”