513,415 U.S. kids have tested positive for COVID-19, report says

New data out Tuesday shows that more than 500,000 children have tested positive for the coronavirus since the pandemic started, according to the American Academy of Pediatrics (AAP). They said children represented 9.8% of all COVID-19 cases in the U.S., where more than 6.3 million total cases have been reported, per a tally by Johns Hopkins University.

The AAP reported there were 70,630 new child cases, a 16% increase over two weeks, between August 20 and September 3, which brings the national total to 513,415. Puerto Rico was among six states and territories that showed an increase in child cases.

The AAP and the Children's Hospital Association compiled the data of children of varying ages as reported by 49 state health departments, New York City, Puerto Rico and Guam. Texas was excluded from the analysis, the AAP noted.

Data from the American Academy of Pediatrics show the percent increase in child cases of COVID-19 between August 20 and September 3, 2020. The data was derived from 49 states, New York City, the District of Columbia and Puerto Rico. Texas was excluded from the count.

American Academy of Pediatrics

The report said the cumulative death toll in the U.S. for children due to the coronavirus is 103. In a subset of data that was analyzed from 42 states and New York City, children were 0-0.3% of all COVID-19 deaths, and 18 states reported zero child deaths.

"At this time, it appears that severe illness due to COVID-19 is rare among children," the AAP said. But health experts have said that kids could spread COVID-19.

Meanwhile, the Centers for Disease Control has issued new data about a deadly and mysterious pediatric illness with potential links to the coronavirus. Since mid-May, the CDC has been following an outbreak of Multisystem Inflammatory Illness in Children (MIS-C) or sometimes referred to as PMIS.

The CDC describes it as "a rare but serious condition associated with COVID-19" that sometimes presents after a COVID illness or after contact with someone with COVID-19. Instead of attacking the lungs like the new coronavirus disease does in adults, this syndrome, while seemingly very rare, can trigger serious, even deadly cardiac complications in kids.

As of September 3, the CDC has collected reports of 792 confirmed cases of MIS-C and 16 deaths across 42 states, New York City and Washington, D.C. Other cases are under investigation, according to the CDC.

The CDC's data suggests that "most cases are in children between the ages of 1 and 14 years, with an average age of 8 years." They also note that "more than 70% of reported cases have occurred in children who are Hispanic/Latino (276 cases) or Non-Hispanic Black (230 cases)."

The AAP report was released as thousands of children returned to school this week for in-person classes. On Long Island, parents seemed nervous and excited as they dropped their children off.

Students lined up in Richardson, Texas, for temperature checks before entering the building. Forrester Elementary in San Antonio is usually packed with 850 kids; but this morning, only 53 opted for in-person classes.

"I feel like they're just a little off balance, maybe a little bit with the rooms looking different, everybody wearing masks," principal Kelly Mantle told CBS News. "I think it is going to become a new norm for a little while and children are going to get used to it and we're getting used to it every day that goes by."

The new figures from the AAP have some educators worried, like those in suburban Phoenix, where the first day of in-person classes was canceled after teachers called in sick.

In New York, new cases are up more than 25% compared to two weeks ago. And with New York City schools preparing for in-person classes in the coming weeks, Governor Andrew Cuomo is trying to quell parents' fears.

"We're going to have a COVID report card for every school in the state," he said.

Omar Villafranca contributed to this report.