RECOVER researchers create new tool to identify Long COVID in children 

RECOVER researchers have designed a new way to identify which children are most likely to have Long COVID. Their study findings, published in the Journal of the American Medical Association (JAMA), describe the research that led to the development of this groundbreaking data-driven tool. As researchers continue to refine the tool through future studies, it may eventually be used to diagnose Long COVID in children.

Read the publication: Characterizing Long COVID in Children and Adolescents

Read the news release: NIH-funded study finds Long COVID affects adolescents differently than younger children

What did the researchers do?

Researchers examined the Long COVID symptoms experienced by school-aged children (6–11 years old) and adolescents (12–17 years old) across multiple body areas and organ systems. More than 5,300 children and adolescents recruited from over 60 U.S. healthcare and community settings took part in this study. All of these study participants belong to the RECOVER pediatric cohort, a group of over 14,000 babies, children, and young adults who are contributing to our understanding of and ability to diagnose, prevent, and treat Long COVID. 

Researchers compared the symptoms reported by the children and adolescents who had a medical history that included COVID-19 prior to the symptoms reported by the children and adolescents with those who did not. 3,860 of the 5,300 children and adolescents included in this study had a previous COVID infection.

First, the researchers narrowed the original list of symptoms to include only those present in at least 5 percent of children or adolescents who had a history of COVID-19. Then they used several different statistical methods to determine the chances that a child with long-lasting symptoms had COVID-19. 

Based on these results, the researchers developed a tool called a research index, which measures the changes across a set of many different pieces of data. They used this index to identify which children were most likely to have Long COVID.

Although this index is a valuable tool for advancing our understanding of Long COVID in children, the researchers emphasize that the symptoms it does not include are real, potentially debilitating, and worthy of scientific research and medical attention. Researchers also stress that any single Long COVID symptom has the potential to indicate that a child or adolescent has developed Long COVID.

What did the researchers discover?

Long COVID symptoms vary by age. Researchers found that 18 prolonged symptoms in school-aged children and 17 in adolescents best indicated the presence of Long COVID. 14 of those symptoms were the same in both age groups. 

The symptoms that best indicated a school-aged child had developed Long COVID include:

• Headache (reported by 55% of the school-aged children taking part in the study who were most likely to have Long COVID)
• Having trouble remembering things or focusing (45%)
• Having difficulty sleeping (44%)
• Stomach pain (43%)
• Itchy skin or rash (29%)

The symptoms that best indicated an adolescent had developed Long COVID include: 

• Daytime tiredness/sleepiness or low energy (reported by 80% of the adolescents taking part in the study who were most likely to have Long COVID)
• Body, muscle, or joint pain (61%)
• Headache (56%)
• Having trouble remembering things or focusing (47%)
• Change or loss in smell or taste (34%)

Researchers also identified four distinct groups of symptoms in school-aged children and three in adolescents. For example, school-aged children in the study experienced a group of symptoms that included having trouble focusing and difficulty sleeping; adolescents in the study experienced a cluster of symptoms that included change or loss of taste and smell. The presence of these symptom groups (or clusters) suggests that children of different ages can develop different types of Long COVID.

Why are these findings important?

Children remain an understudied group in Long COVID research compared to adults. The research index RECOVER researchers created in this study is the first data-driven tool for identifying Long COVID in children. In the future, researchers can use this index to answer questions like:

• How does Long COVID impact children’s growth and development?
• Do the different symptom clusters that affect children and adolescents have different causes?

Findings from these future studies could help researchers expand RECOVER’s clinical trials to include promising new treatments.

Read the research Q&A to access frequently asked questions about this study.