Updated August 10, 2021 at 3:01 PM ET

Coronavirus cases among children are rising at a time when the highly infectious delta variant is advancing across the United States at a rapid clip.

New state-level data analyzed by the American Academy of Pediatrics and the Children's Hospital Association shows that children accounted for roughly 15% of all newly reported COVID-19 cases across the nation for the week ending on Aug. 5.

Nearly 94,000 child cases of COVID-19 were recorded during that period, a 31% increase over the roughly 72,000 cases reported a week earlier. In the week before then, there were 39,000 new child cases.

The American Academy of Pediatrics and the Children's Hospital Association said that new coronavirus cases in children have been increasing since July after a period of decline in the early summer.

"This virus is really tracking the unvaccinated," said Dr. Yvonne Maldonado, a professor of pediatrics and infectious diseases at Stanford University. "Because children under 12 are not able to be vaccinated, we're just seeing the same increase in infections in that group because [the delta variant] is so infectious."

Parents are searching for answers

One big question for parents — whether delta is making kids sicker than previous strains — still has no clear answer.

But the numbers appear to show that severe illness, hospitalization and death are rare in children infected with the coronavirus.

In states where data was available, less than 2% of all child COVID-19 cases required hospitalization and 0.00% to 0.03% were fatal.

"I'm not seeing any patterns that suggest the virus is more virulent or more serious or more severe in children than it was before this variant appeared," Maldonado added.

Concerns about the strain on the pediatric health care system

Still, the growing number of children hospitalized with COVID-19 could further strain an already overburdened pediatric health care system.

Many children's hospitals are not only dealing with patients who've contracted the coronavirus but also kids with issues indirectly related to the pandemic. Many children have developed mental health problems stemming from social isolation, and others deferred medical care during the peak of the outbreak last year.

"These kind of indirect impacts of COVID have actually been a much bigger volume impact on pediatric intensive care capacity than the direct count of COVID kids," said Mark Wietecha, CEO of the Children's Hospital Association.

Despite no sharp rise in the number of hospitalizations, Wietecha said many children hospitalized with COVID-19 now, likely driven by the delta variant, are sicker than those who had contracted previous strains. While the overall picture remains unclear, he said pediatric hospitals are nonetheless now in need of specially trained medical staff who understand the unique requirements of treating young patients.

Cases are spiking in children as many of them prepare for the start of a new school year, which is now tinged with uncertainty. Some states are attempting to block school districts from requiring students to wear masks.

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