FRIDAY, Sept. 17, 2021 (HealthDay News) -- In kids and teens, symptoms of long COVID rarely last more than 12 weeks, a new international study reports.
The researchers also found that exposure to the highly contagious Delta variant did not result in more serious disease in children compared to earlier variants, and that most cases of COVID-19 were asymptomatic or mild.
Despite those reassurances, the study did include a troubling finding: Young people with pre-existing conditions — such as obesity, chronic kidney disease, heart disease or immune disorders — are 25 times more likely to get severe COVID-19 than kids without pre-existing conditions. A recent review found that severe COVID-19 occurred in 5% of those with pre-existing conditions and less than 1% of others, the researchers said.
"More data is needed to describe the burden of COVID-19 in children and adolescents following the emergence of the highly transmissible Delta variant and because adults have been prioritized for vaccines," said Andrew Steer from the Murdoch Children's Research Institute (MCRI), in Melbourne, Australia.
And long COVID symptoms were hard to separate from indirect effects of the disease on kids, such as school closures and being unable to spend time with friends or do sports or hobbies, said Dr. Petra Zimmermann of the University of Fribourg, in Switzerland.
"This highlights why it's critical that future studies involve more rigorous control groups, including children with other infections and those admitted to hospital or intensive care for other reasons," she said in an MCRI news release.
Study co-author Nigel Curtis of the MCRI said that although kids with COVID-19 are usually asymptomatic or have mild disease with low rates of hospitalization, the risk and features of long COVID have not been well understood.
For this study, the researchers reviewed 14 published studies that included more than 19,400 children and teens. The investigators found that the most common symptoms of long-haul COVID over four to 12 weeks were headache, fatigue, sleep disturbance, difficulty concentrating and abdominal pain.
Curtis said it was reassuring that there was little evidence that symptoms lasted more than 12 weeks, suggesting long COVID might be less of a problem in young people than in adults.
"The low risk posed by acute disease means that one of the key benefits of COVID vaccination of children and adolescents might be to protect them from long COVID," Curtis said. "An accurate determination of the risk of long COVID in this age group is therefore crucial in the debate about the risks and benefits of vaccination."
Steer added that, as pandemic restrictions ease and other respiratory viruses circulate, researchers need to learn whether co-infection with such viruses as respiratory syncytial virus or influenza increases COVID-19 severity in young people.
The findings were published online Sept. 16 in the Pediatric Infectious Disease Journal.
For more on COVID-19, head to the U.S. Centers for Disease Control and Prevention.
SOURCE: Murdoch Children's Research Institute, news release, Sept. 16, 2021