WASHINGTON – A large analysis published last week in the journal Pediatrics underscores the toll long Covid can take on children, in some cases leading to neurological, gastrointestinal, cardiovascular and behavioural symptoms in the months after an acute infection.

“Long Covid in the US, in adults and in kids, is a serious problem,” said Dr Ziyad Al-Aly, chief of research and development at the Veteran Affairs St Louis Health Care System and a clinical public health researcher at Washington University in St Louis, who studies the condition but was not involved in the new report.

He said the paper, which drew on numerous studies of long Covid in children, was “important” and illustrated that the condition can affect multiple organ systems.

The new review suggested that 10 per cent to 20 per cent of children in the United States who had Covid-19 developed long Covid.

But Dr Suchitra Rao, a paediatric infectious disease expert at Children’s Hospital Colorado and co-author on the paper, said there are “lots of caveats” with the prevalence estimates used to arrive at that number.

For example, some studies included looked only at the very small percentage of children who were hospitalised for Covid-19.

Like adults, children who had more severe cases of Covid-19 have a greater risk of lingering symptoms or new complications.

Data from the Centres for Disease Control and Prevention suggests the prevalence of long Covid is closer to 1 per cent to 2 per cent of children who have had Covid-19.

Dr Al-Aly said in adults, the number was likely to also be in the single digits.

Dr Stephen Freedman, a professor of paediatrics and emergency medicine at the University of Calgary Cumming School of Medicine, said generally speaking, most parents should not be worried that their children will develop long Covid.

“I don’t get asked a lot, if at all, about ‘Is my child now at risk of developing long Covid?’ after we diagnose them with an acute infection,” he said. “And I think that’s appropriate.”

What does long Covid look like in kids?

Long Covid can be challenging to study, in part because it is difficult to diagnose, as the symptoms are so wide-ranging.

Making a diagnosis is perhaps even trickier in children because symptoms may present differently from how they appear in adults.

Young children may also not have the language to describe what they are feeling, so researchers advised parents to look for changes in behaviour.

Fatigue, brain fog and headaches are among the most frequently reported symptoms of long Covid in children.

While these issues are sometimes on the mild end of the spectrum, they can prevent kids from participating fully in school or recreational activities.

Young children may also act out, frustrated that they cannot easily do what they used to.

Most symptoms improve within a year, experts said, but for some children they can persist for longer.

It is still not clear what the long-term impact of these prolonged symptoms may be on children’s development, said Dr Laura Malone, director of the Pediatric Post-Covid-19 Rehabilitation Clinic at Baltimore’s Kennedy Krieger Institute.

In severe cases, some children experience lingering respiratory and cardiovascular problems, including the heart condition, myocarditis.

Diabetes and other autoimmune disorders can also emerge on the heels of a Covid-19 infection, although these “tend to be much, much less prevalent in kids” than more mild symptoms, Dr Al-Aly said.

Dr Sindhu Mohandas, an infectious disease specialist at Children’s Hospital Los Angeles, said persistent and severe symptoms can emerge even in children with mild infections.

That was the case for Lucas Denault, whose initial brush with Covid-19 in 2021 did not include much beyond a stuffy nose. Lucas, then 15, recovered and went back to school, track practice and student council meetings.

But months later, he started struggling to walk down the halls of his high school in Littlestown, Pennsylvania. His head and chest ached. He felt dizzy and nauseated.

“It was just such a quick downfall,” said his mother, Ms Karin Denault.

Neither Lucas nor his mother had considered that his issues could be linked to his brief bout of Covid-19. But at the recommendation of a relative, he went for an evaluation at the Kennedy Krieger clinic in Baltimore.

There, he was diagnosed with long Covid and with postural orthostatic tachycardia syndrome, a cluster of symptoms that lead to extreme fatigue and can occur among people with long Covid.

What treatments are available?

There are no drugs approved to treat long Covid, so doctors focus on managing symptoms and helping patients function day to day.

Some doctors will prescribe medications to address issues such as headaches and muscle pain.

Dr Mohandas, who was also involved in the research review, said much of the work she and other clinicians do revolves around validating the experiences of these young patients.

Many “had previously been very healthy, so frequently, everyone tends to doubt their symptoms”, she said.

Dr Malone said schools should make accommodations for children who are struggling, including breaks during the day and extra time for tests.

Small changes helped Lucas. It was difficult for him to push himself out of bed, for example, so he started sleeping upright to make it easier.

At his doctor’s suggestion, he sometimes dangled his feet off the bed and spelt his name with his toes to improve blood flow.

His doctor also prescribed several medications, including a blood pressure drug, to help manage symptoms such as fatigue and brain fog.

Lucas is now a freshman at Princeton University, and most of his symptoms have improved.

When he was touring colleges, his mother often had to push him in a wheelchair. Recently, she came to campus to watch him play club basketball. NYTIMES