Children, like adults, are at risk of developing "long COVID." But experts are still struggling to understand what, exactly, that risk level is.

Why it matters: As the work to determine how common certain coronavirus vaccine side effects are in children, it's important to balance these risks against the risk of children remaining unvaccinated — which includes their risk of long-term health issues if they get infected.

The big picture: Pediatricians across the country say it's unclear how common long COVID is in children.

• That's in part because we don't know how many kids have been infected by the virus. But it's also because "most kids with COVID long-haul aren’t coming to the surface. We’re not finding them," said Amy Edwards, a pediatric infectious diseases specialist at University Hospitals Rainbow Babies & Children's Hospital in Cleveland, Ohio.
• "We don’t know the numerator or the denominator," she said, adding that the condition is probably less common in children than adults.

Between the lines: Parents have been trying to balance the pandemic's risk to children with its disruption to their lives for more than a year. Kids generally don't get as sick from the virus as adults do, although a small percentage do have severe cases.

• Parents of young children are still trying to figure out how to handle the country reopening while waiting for their kids to become eligible for vaccines. And plenty of parents are hesitant for their kids to be vaccinated at all, regardless of their age.
• Emerging evidence about a possible link between mRNA vaccines and myocarditis in young people could further heighten parents' fears, although experts caution that remaining unvaccinated is still the larger risk for children.

Details: Long COVID is different from multisystem inflammatory syndrome (MIS-C) in children, another condition that children can develop after their initial coronavirus infection.

• Long COVID is "more an overall general sense of unwellness opposed to a massive inflammatory response that lands them in the hospital," Edwards said. "COVID long haul is more poor recovery...they just never quite get better.”
• Long COVID appears to be more common in teenagers than younger children, experts said. Otherwise, there's not a lot of information about who's at the highest risk.
• Common symptoms include shortness of breath, chest pain and fatigue, said Ixsy Ramirez, a pediatric pulmonologist at C.S. Mott Children’s Hospital in Ann Arbor, Mich. She said that a lot of the children she's seeing were previously healthy and not the kids that she would have guessed would be at risk.

State of play: Some experts said they're seeing more long COVID in children now than they did earlier in the pandemic, but it's unclear why.

• One reason may be because parents weren't sure for a while whether their kids were sick or just generally off-kilter from lockdowns and social distancing.
• “We don’t know what the duration is or what is the best way to treat these patients," said Beth Theilen, an infectious diseases professor at the University of Minnesota Medical School in Minneapolis.

The bottom line: "We're in a place with COVID long haul, especially with kids, that we don’t know what we don’t know," Edwards said.