Less common than in adults, the condition can be hard to diagnose in children. Growing research is helping scientists understand the symptoms—and risks—for young people.
Science – National Geographic – 2 November
Owen, 11, was the last in his family to get COVID-19. While everyone else recovered within two weeks, his symptoms lingered. Over the next few weeks his vision blurred, his skin turned pale, he began forgetting things, and every night he experienced excruciating pain in his chest and abdomen. “You just didn’t know if he was going to be with you tomorrow,” says Owen’s mother, Susie.
An eye exam, a chest X-ray, and a heart monitoring test called an echocardiogram were all normal. The doctors ruled out multisystem inflammatory syndrome, a rare but serious condition linked to COVID. Only when a friend of Owen’s mother suggested that her son might have long COVID did she consider the possibility. “Neither my husband nor I had information on hand about long COVID,” says Susie, who asked that we don’t use her last name to protect her son’s privacy. Owen’s pediatrician hadn’t mentioned the possibility of long COVID or specific steps to combat his lingering symptoms, she says.
Long COVID is less common in children than in adults, but more researchers have been trying to understand the condition in kids and determine who might be at risk as the pandemic has continued. Currently there are only about a dozen pediatric long COVID clinics in the U.S., according to a list maintained by a support group called long COVID Families. “Early in the pandemic there was a thought that children were somehow sort of immune to COVID,” says Laura Malone, a pediatric neurologist at the Kennedy Krieger Institute’s Pediatric Post-COVID-19 Rehabilitation Clinic in Baltimore, Maryland. But that notion changed, particularly after Omicron’s arrival. “Now there’s more recognition that a lot of children do well and recover after a COVID infection,” she says, “but there’s a need to remain vigilant and be aware that a subset of children can continue to have some difficulty.”
By late February, Owen, who was energetic prior to COVID, struggled to walk short distances. “Literally walking to the end of the driveway was difficult for him,” Susie says. Instead of attending school full-time, Owen opted for half days. But when the pain and the weakness was too much, resting at home was his only option. Seeing Owen lying on the couch, not wanting to get up, was heart-wrenching, Susie says.
In most cases, symptoms resolve within one to five months, but in some children they can last longer. Here’s what we know about the condition in kids.
What pediatric long COVID looks like
According to several studies, the most common long COVID symptoms in children are headaches, fatigue, mood swings, difficulties concentrating, sleep disturbances, and abdominal pain.
“It’s probably a grab bag of many things,” says Betsy Herold, a pediatric infectious disease physician at the Albert Einstein College of Medicine in New York City, “and we don’t know that everything we’re calling long COVID is the same thing.”
In children, symptoms may be tricky to diagnose, especially among much younger kids who can’t describe how they feel. Complicating the diagnosis is the difficulty of distinguishing symptoms linked to a COVID infection from those arising out of pandemic life, such as sporadic schooling, lockdowns, and social isolation.
To tackle that problem, scientists from the Centers for Disease Control and Prevention compared nearly 780,000 children who were COVID-19 positive with more than 2.3 million who weren’t to identify symptoms linked to the virus alone. In a recent report they showed that, although uncommon, those with COVID-19 were more likely to report some loss of smell and taste, circulatory issues, fatigue, and pain even after 31 to 365 days following infection. Similarly, their chances of developing inflamed heart muscles, type I diabetes, blood clots in veins, and kidney failure—although rare—were also higher.
How prevalent is long COVID in kids
In a June 2022 analysis, scientists reviewed 21 long COVID studies and estimated that about 25 percent of the nearly 80,000 kids and adolescents who contracted COVID had at least one or more symptoms lasting longer than 28 days after infection. Among the hospitalized, that proportion jumped to 29 percent.
But other studies suggest the true figure is lower. A July 2022 multi-country study of nearly 1,900 COVID-positive children found that long COVID rates 90 days after infection were 5.8 percent; 9.8 percent among the hospitalized.
Another report using health records from nine children’s hospitals in the U.S. found long COVID symptoms in 3.7 percent of the patients. “In some sense that’s reassuring,” says Suchitra Rao, an infectious disease pediatrician at the Children’s Hospital Colorado and lead author of the study. “It is not as common as we first thought, and that’s what some other studies are showing us as well.”
Compared with adults, however, long COVID seems much less common in kids and adolescents. Perhaps that is because they produce higher antibody levels that persist longer and can clear the virus faster, says pediatric infectious diseases expert Roland Elling at the University of Freiburg in Germany.
But varying follow-up periods after a COVID-19 infection makes it difficult to compare studies estimating the disease burden. Also, how, when, and why long COVID symptoms develop hasn’t been as well studied in children as in adults. “It’s just a lot harder getting blood and following children the way these studies were done in adults,” says Joshua Milner, a pediatric allergy and immunology specialist at the Columbia University Irving Medical Center in New York City.
Other than children with severe COVID-19 or chronic medical conditions, and those who are unvaccinated, Rao’s research indicated that kids younger than five years old also had a higher risk of developing long COVID. Whether that’s a result of parents being more likely to bring young kids to their doctor or a true physiological effect among that age group remains to be seen, Rao says. However, most studies so far have found that it’s teenagers, particularly females, who report persistent symptoms.
Ongoing clinical trials
Scientists in the United Kingdom have been using online surveys since March 2021 to follow 30,000 teenagers, half of whom were COVID-19-positive, at three, six, 12, and 24 months after their first laboratory-confirmed diagnosis. The so-called CLoCk study revealed that many participants with persistent symptoms like fatigue and shortness of breath recover within six months, says Terence Stephenson, a pediatrician at the University College London who’s leading the research.
But a different cohort seemed to develop these conditions beginning at the six-month follow-up; these teens seemed to get better at 12 months. Why and when these symptoms emerge is hard to explain, he says, and it’s possible that some teenagers were reinfected, while others may be responding to the pandemic lifestyle.
Stephenson’s team will follow the trial participants, who self-report their health status. But they are also planning to conduct brain and heart scans, as well as exercise tests, among a subset with unresolved long COVID symptoms to spot any abnormalities.
In the U.S., the National Institutes of Health is funding a similar trial to understand long COVID in children, determine how many it affects, and devise potential treatments.
In April, Owen’s mother sought help from the Kennedy Krieger Institute, where physicians helped her plan a diet that would reduce inflammation and used physical therapy, to help Owen recover. “Managing his activity, not letting him do too much was a big part of getting through this,” Susie says. But she also acknowledges that some healing may have occurred naturally over time.
Although Owen still struggles with some fatigue and shortness of breath, his chest and stomach pain, blurry vision, and memory issues have largely subsided. He’s back to school full-time but taking a year off soccer; instead, he’s taken up swimming.
While Malone and others are working to help patients like Owen, they’re hoping more research will lead to better pediatric long COVID treatments. We’ve learned a lot in the past two years, she says, but what causes long COVID in some children versus others and how best to care for them remains unresolved, much like in adults.”