Kids who catch COVID are usually asymptomatic or have mild illness, particularly if they don’t have underlying conditions. Between 15 percent and 42 percent of children and adolescents with COVID don’t develop any symptoms, and recently only 0.1 percent to 2 percent of kids with COVID have ended up in the hospital. It’s one of the few consistent points of light in the COVID-19 pandemic. But what of long COVID? Reports of kids with a mild sickness developing long haul COVID symptoms, such as headache and fatigue that last for weeks or months, is surely one of the biggest fear factors today for cautious parents. The fears, like the misleading reports and flawed studies that drive them, are overblown. Long COVID can happen, in adults and kids, but it’s ill-defined and vanishingly rare in the latter group.
Many of the studies on long COVID in kids have serious flaws that have gone overlooked. A new review of the 14 existing studies on the topic, led by the Murdoch Children’s Research Institute in Australia, shows that very few children have symptoms that last for more than 12 weeks after COVID. In those that do, COVID might not even be the cause. The short of it? Parents can stay cautious, but take a (masked) breath. The dangers kids face are, at this point in the pandemic, not particularly worrisome compared to the normal risks of everyday life.
What is Long Haul COVID, and How Long Is it?
Long COVID is one of the most mysterious COVID unknowns. Both adults and kids can have the condition, but much more is known about it in adults. In children, the most common symptoms are headache, fatigue, sleep disturbance, difficulty concentrating, and abdominal pain, according to the new review, which included 14 studies that collectively enrolled nearly 20,000 children participants.
Researchers don’t agree on how long symptoms have to last after infection to count as long COVID. It usually takes several weeks to recover from infection. So symptoms have to last for at least that many weeks to months to be considered long COVID. A study in the journal Nature classifies long COVID to be when symptoms last for at least two months. Other experts only include symptoms lasting at least 12 weeks.
But the new review study found that kids who have had COVID rarely report symptoms that last more than 12 weeks. And one previous study found that most kids who had symptoms four weeks post-COVID saw them resolve by eight weeks.
In other words, most long COVID in kids isn’t actually that long.
Long Haul COVID Might Not Actually Be Caused By COVID
Out of the 14 available studies, the new review finds that only five included kids and teens that didn’t have COVID as controls. Of those five, two studies didn’t find long-lasting symptoms to be more common in kids that had COVID compared to those who didn’t. That’s a major red flag. But how is it possible?
More than 200 symptoms have been said to be linked to long COVID. A lot of those symptoms — headaches, fatigue, etc. — can be caused by many things other than the coronavirus. One major cause is, of course, living through a pandemic, with school closures, social isolation, and chronic stress all playing a role.
“If you don’t include a group of children who haven’t had COVID, you simply can’t tell whether the symptoms are above and beyond what a control group would experience,” says Logan Spector, PhD, Division Director of Epidemiology and Clinical Research at the University of Minnesota Medical School, who was not involved in the study. “There’s just no way to make sense of the data without comparison.”
The review isn’t the first study to point out this issue. One large preprint study that hasn’t yet been peer-reviewed found that among older kids who had tested positive for COVID, 65 percent reported at least one symptom after 15 weeks. Among those who had never tested positive, 53 percent reported symptoms. They’re just that common.
So when you actually look at long COVID, it’s not that long, and many cases probably aren’t even caused by COVID.
How Common Is Long COVID in Kids?
All that said, some kids still do get long COVID. It’s just unclear how many. One previous study reported that as many as one in seven kids with COVID become so-called long-haulers. But the new review calls this into question.
For starters, the studies that have been conducted on long COVID in kids are flawed. As mentioned above, not using kids without COVID as a control group way overestimates “long COVID” symptoms since so many people experience them in everyday life. Additionally, some researchers recruited participants from support groups for parents of kids with long COVID, which likely skewed their results. And many of the studies had a low response rate. In one, only 13 percent of those asked to respond to the survey did so. People who responded to the survey were more likely to be those experiencing symptoms, which also throws off the findings, experts say.
You can’t really blame the researchers for these issues. “This is to be expected,” Spector says. “There were a lot of people scrambling to get any sort of data in an emergency circumstance… Unfortunately, that means we’re not really going to find out answers for still some time.”
Spector stresses that this doesn’t mean that long COVID in kids isn’t real or an issue. Experts don’t have enough data yet to say either way. “What we have now is more like an absence of evidence, or something close to it, because the studies have been — to jump out of scientific mode — just kind of all over the place in quality,” he says.
The uncertainties around long COVID are one reason why experts are pushing vaccines for kids — because we don’t know how common or severe long COVID is for them. But the evidence also doesn’t support parents stressing over their child getting the condition. Besides, that stress could cause symptoms that they could actually mistake for long COVID.