How Common Is Long COVID in Children and How Is It Different Than in Adults?

According to a new review, long-term COVID symptoms rarely lasted longer than 12 weeks in children and adolescents, unlike adults. Credit: master1305

Long COVID symptoms rarely lasted longer than 12 weeks in children and adolescents, unlike adults. But according to a review led by the Murdoch Children’s Research Institute (MCRI), more studies were needed to examine the risk and impact of long-term COVID in young people to guide vaccine policy decisions in Australia.

The review, published in the Pediatric Infectious Disease Journal, found that existing studies of long-term COVID in children and adolescents have significant limitations, and some show no difference in symptoms between those infected with SARS-CoV-2 and those who have it. t.

It comes as a new MCRI COVID-19 research letter also stating that after 10 months in circulation, the Delta strain had not caused more severe disease in children than previous variants and most cases remained asymptomatic or mild.

However, it was found that children and adolescents with pre-existing health problems, including obesity, chronic kidney disease, cardiovascular disease and immune disorders, have a 25 times greater risk of severe COVID-19. A recent systematic review reported that severe COVID-19 occurred in 5.1 percent of children and adolescents with pre-existing conditions and 0.2 percent without.

MCRI professor Nigel Curtis said that while children with SARS-CoV-2 infection were usually asymptomatic or had mild illness with low hospitalization rates, the risk and characteristics of long-term COVID were poorly understood.

“Current studies lack clear case definition and age-related data, have variable follow-up times, and rely on self- or parent-reported symptoms without laboratory confirmation,” he said. “Another important issue is that many studies have low response rates, which means they may overestimate the risk of long-term COVID.”

MCRI and University of Friborg Dr. Petra Zimmermann said long-term COVID-19 symptoms have been difficult to distinguish from those due to the indirect effects of the pandemic, such as school closures, not seeing friends or being unable to exercise and hobbies.

“This highlights why it is critical that future studies include more rigorous control groups, including children with other infections and those who are hospitalized or in intensive care for other reasons,” she said.

The MCRI-led review analyzed 14 international studies of 19,426 children and adolescents who reported persistent symptoms after COVID-19. The most common symptoms reported four to 12 weeks after acute infection were headache, fatigue, sleep disturbances, difficulty concentrating and abdominal pain.

Professor Curtis, who is also a professor of pediatric infectious diseases at the University of Melbourne and head of infectious diseases at the Royal Children’s Hospital, said it was reassuring that there was little evidence that symptoms lasted longer than 12 weeks, suggesting that COVID-19 may less. worrisome in children and adolescents than in adults.

But he said further studies were urgently needed to inform policy decisions about COVID vaccines for children and adolescents.

“The low risk of acute illness means that one of the main benefits of COVID vaccination of children and adolescents could be to protect them from long-term COVID,” he said. “An accurate assessment of the risk of long-term COVID in this age group is therefore crucial in the debate about the risks and benefits of vaccination.”

The MCRI COVID-19 briefing also confirmed research gaps surrounding the role of the Delta variant in COVID-19 disease in children and adolescents.

MCRI COVID-19 Governance Group Co-Chair Professor Andrew Steer said that because the Delta variant was more transmissible, controlling outbreaks in the community was challenging without risk mitigation strategies.

“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 as vaccines have been prioritized for adults,” he said.

“As restrictions ease and other respiratory viruses in circulation increase, we also need to understand whether co-infection with other respiratory viruses, such as RSV or influenza, increases disease severity in young people.”

But Professor Steer said parents should be reassured that illness caused by the Delta variant remained asymptomatic or mild in the vast majority of children and adolescents and that hospitalizations were still uncommon.

To date, there have been no deaths from COVID-19 in children under 10 and one death in an adolescent in Australia. As of September 5, 22 percent of all COVID-19 cases were among those under the age of 19.

The COVID-19 briefing stated that while childhood multisystem inflammatory syndrome (MIS-C) had caused infant deaths abroad, these were mainly early in the pandemic and earlier diagnosed, but more appropriate treatments had produced better outcomes. By 2021, almost all children with MIS-C made a full recovery. In Australia, there are four confirmed cases and no deaths from MIS-C.

Reference: “How common is long-term COVID in children and adolescents?” by Zimmermann, Petra MD, PhD; Pittet, Laure F. MD-PhD; Curtis, Nigel FRCPCH, PhD, Sept. 16, 2021, Pediatric Infectious Disease Journal.
DOI: 10.1097/INF.0000000000003328

Researchers from Friborg Hospital HFR, the University of Melbourne, the University Hospitals of Geneva and the Royal Children’s Hospital also contributed to the systematic review.