At least 97,000 children tested positive for the coronavirus during the last two weeks of July, according to a new review of state-level data by the American Academy of Pediatrics and Children's Hospital Association. The increase represents a 40% surge in the nation's cumulative total of child cases.

"I think it's showing that, yes, kids can get infected and can spread the infection," said Dr. Sean O'Leary, a pediatric infectious disease specialist at Children's Hospital Colorado and vice chair of the Committee on Infectious Diseases for the American Academy of Pediatrics.

The report comes as schools across the country grapple with when and how to reopen safely — with those decisions becoming increasingly politicized. President Trump has attempted to pressure the nation's K-12 schools to reopen, threatening to withhold federal funds and falsely claiming in an interview last week onFox & Friends that "children are almost, I would almost say definitely, but almost immune from this disease."

This new report reiterates that children are not, in fact, immune to this disease.

Since the beginning of the pandemic, at least 340,000 children have tested positive for the coronavirus, representing roughly 9% of U.S. cases to date. The rise in child cases, according to the report, was largely fueled by states in the South and West, including Missouri, Oklahoma, Georgia, Florida, Montana and Alaska.

The report comes with a few important caveats. The uptick in cases is due, in part, to an increase in testing. Different states also define a "child" differently. For data reporting purposes, a majority of states use an age range between 0-17 and 0-19, but, in Tennessee and South Carolina, the cutoff is 20. In Alabama, it's 24. Also, according to the report, the number of positive tests among children could be far higher because of incomplete reporting from New York and Texas. In fact, Texas provided age distribution for just 8% of its confirmed COVID-19 cases and was excluded from many of the report's findings.

If there is good news in such a report, it's that, in spite of the uptick in child infection rates, the data also show that most children do not get critically ill with the disease and that, among the states that reported hospitalization data, the current hospitalization rate for children remains low, at 2%. What's less clear is how effectively children would spread the virus in a classroom setting, not only to friends and classmates but to teachers and school staff.

Data from South Korea suggest that children younger than 10 may not spread the disease easily, but that teenagers do — perhaps as effectively as adults. The Centers for Disease Control and Prevention offers another cautionary tale, for schools considering reopening: In late June, the disease spread quickly among staff and children at a Georgia sleepaway camp. In a matter of days, at least 260 campers and teen staffers tested positive. Interestingly, of the campers tested, the youngest campers, ages 6 to 10, had the highest infection rate: Fifty-one percent tested positive.

In recent weeks, school districts across the country have announced their plans for the fall. Last week, Chicago became the latest big-city district to announce it would not yet allow students to return to classrooms because of a recent surge in coronavirus rates there.

"While Chicago remains in a better place than many other regions of the country," said Dr. Allison Arwady, the Chicago Department of Public Health commissioner, "these recent trends are very concerning."

But in many communities, the decision to reopen schools is being driven by politics, not local public health conditions. In Florida and Texas, some public health officials have been reportedly sidelined by state leaders who have been outspoken in their desire for schools to reopen quickly.

In a recent review of school reopening plans and local voting trends, Jon Valant of the Brookings Institution found no relationship statistically between reopening decisions and counties' new COVID-19 cases per capita. Instead, he found that "on average, districts that have announced plans to reopen in person are located in counties in which 55% voted for Trump in 2016, compared [with] 35% in districts that have announced plans for remote learning only."

Last week, students at Georgia's North Paulding High School posted photos and videos showing packed hallways at the school and few students wearing face coverings. Though the district is in an outer suburb of Atlanta, where infection rates remain relatively high, schools reopened for in-person instruction last week. This weekend, though, the school reported that six students and three staff members have tested positive for the coronavirus and that in-person classes would temporarily move online to give the school time to disinfect.

What does all this mean for schools?

"In places where there is really good control of the virus," O'Leary said, "with mitigation measures in place, I think it's reasonably safe to open schools. We're never going to get to zero risk."

New York City is a prime example of a school district that plans to reopen its schools partially this fall because the broader community followed safety guidelines and dramatically reduced infection rates, with 1% of coronavirus tests now turning out positive.

But in places where the virus is still spreading widely, O'Leary said, these new data are an important reminder that reopening schools may not be safe. If the coronavirus is circulating in a community, he said, it is inevitable it will follow students and staff to school.

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