After declining in the early summer, child COVID-19 cases have steadily increased again in recent weeks -- just as many kids head back to the classroom.
In a newly released weekly report, which compiles state-by-state data on COVID-19 cases among children, the American Academy of Pediatrics (AAP) and the Children's Hospital Association (CHA) found that nearly 94,000 new child COVID-19 cases were reported last week, a continued "substantial" increase.
"This is not your grandfather's COVID," Dr. Mark Kline, the physician in chief of Children's Hospital New Orleans told ABC's "Good Morning America" Monday. Louisiana is facing the nation's highest rate of new COVID-19 cases with the Children's Hospital in New Orleans describing what they're seeing as "an epidemic of very young children."
"We are hospitalizing record numbers of children," Kline continued. "Half of the children in our hospital today are under two years of age. Most of the others are between five and ten years of age -- too young to be vaccinated just yet."
In Florida, the state with the highest number of confirmed pediatric COVID-19 hospitalizations in the country, 179 patients are receiving care, according to federal data. As of Monday morning, Nicklaus Children's Hospital in Miami had one child on a ventilator.
Dr. Marcos Mestre, the hospital's vice president and chief medical officer, told ABC News that in recent weeks, his teams have seen a "significant uptick" in pediatric COVID-19 cases. He said some children are alone in the hospital because their parents, also unvaccinated, are battling COVID-19 at another hospital.
"It's tough," he said, and places "undue social stress on the child, as you can imagine, not having the parents around."
Texas follows Florida closely behind with 161 confirmed pediatric patients hospitalized across the state, and in California, there are 98 confirmed pediatric patients receiving care.
It comes as the country's daily case average for Americans increased to nearly 100,000 cases a day for the past four days -- up by 31.7% in the last week and nearly nine times higher than the average was in mid-June. For children 17 and under, the rate of pediatric hospital admissions per capita is 3.75 times higher than it was just a month ago -- now equal to its highest point of the pandemic, in January 2021.
While severe illness due to COVID-19 remains "uncommon" among children, experts say the increased trend is concerning.
"While severe outcomes of COVID-19 infection in pediatric populations continue to be relatively low compared to adults, the current exponential growth in hospitalizations is a very worrisome trend," explained Dr. John Brownstein, an epidemiologist at Boston Children's Hospital and an ABC News contributor. "As the remaining population ineligible for the vaccine, children will, unfortunately, be the main vectors of virus spread creating risk to both themselves and the rest of the population."
The Food and Drug Administration has not yet approved vaccines for children under 12, leaving a large youth population susceptible to COVID-19. But following data released by the AAP last week showing the massive increase in COVID-19 cases among kids, the organization wrote a letter to the head of the FDA urging authorization of vaccines for 5-11-year-olds as fast as possible.
"We understand that the FDA has recently worked with Pfizer and Moderna to double the number of children ages 5-11 years included in clinical trials of their COVID-19 vaccines. While we appreciate this prudent step to gather more safety data, we urge FDA to carefully consider the impact of this decision on the timeline for authorizing a vaccine for this age group," wrote Dr. Lee Savio Beers, president of the AAP.
"Simply stated, the delta variant has created a new and pressing risk to children and adolescents across this country, as it has also done for unvaccinated adults," she said.
Beers told ABC News Live's "The Breakdown" Monday that hospital workers are inundated with the massive increase in COVID-19 cases among kids particularly in areas where vaccinations are low.
"They're seeing just a lot of kids who are very ill with COVID. They're seeing children in their ICUs. They're seeing children who are in pretty significant distress," she said, reiterating the organization's position that the FDA could approve vaccines for 5 to 11 years olds based on previous trials.
"We know that [COVID] can be severe in children, and so we should do those things that we need to do to help prevent the spread and help keep our kids and our whole community safe," she added.
Dr. Ashish Jha, who supports expanding vaccinations for those 5 to 11, reiterated on ABC's "Good Morning America" Monday the position widely shared by public health experts that the first step to getting kids back to school safely is with vaccinations for everyone who is eligible.
"Kids who can't get vaccinated, you protect them by making sure everyone around them is vaccinated," he said.
A recent CDC national immunization survey from late July found that among parents of children 13 to 17, 49.8% had children vaccinated or definitely plan to vaccinate, 25.4% were "probably will get their children vaccinated or are unsure", and 24.8% are reluctant, "probably or definitely will not get children vaccinated."
Despite the delta surge, a recent Kaiser Family Foundation poll found among unvaccinated adults, nearly half, 46%, say they definitely won't get a shot, 15% call it very unlikely and 10% somewhat unlikely. In another question, one in five of the unvaccinated say news about variants has made them more apt to get a jab.
As pediatric hospitalizations rise, especially where vaccination rates are low, Dr. Peter Hotez of Baylor College of Medicine called what's unfolding in the South a "humanitarian catastrophe."
"As schools act as an accelerant you should assume we're going to see pediatric intensive care units all across the South completely overwhelmed and even a possibility of small tent cities of sick adolescents and kids," he told MSNBC's "Morning Joe," adding the slope is "going up and up."
Less than 30% of Americans ages 12 to 15, and only 41% of Americans 16 to 17 are fully vaccinated, according to the CDC.
"And now schools are going to be an extraordinary accelerant," he added. "If your adolescent kid is unvaccinated, you should assume there's a high likelihood that that child is going to get COVID."
"I hope -- I don't predict -- I hope that it will be within the next few weeks. I hope it's within the month of August," Fauci said of full FDA approval on NBC's "Meet the Press." "If that's the case, you're going to see the empowerment of local enterprises, giving mandates that could be colleges, universities, places of business, a whole variety and I strongly support that. The time has come."
But there's opposition -- and it could be heard by the Supreme Court.
A group of eight unvaccinated University of Indiana students made an 11th-hour appeal to the Supreme Court last week to block the school's vaccination mandate for anyone on campus this fall. They put forth various arguments for why the mandate allegedly violates their constitutional rights and heightened legal scrutiny, including that it's contrary to FDA's emergency use authorization terms for the vaccines -- which public health experts are hoping changes soon. The students asked for a decision by Friday.
ABC News' Gary Langer, Cheyenne Haslett and Senior Washington Reporter Devin Dwyer contributed to this report.