Nearly 72,000 children in the U.S. tested positive for COVID-19 last week, a massive jump from the approximately 39,000 cases among kids one week earlier, according to a new report from the American Academy of Pediatrics and the Children’s Hospital Association.

Children represented 19% of all COVID-19 cases for the week ending July 29.

Severe illness due to COVID-19 remains "uncommon" among children, the two organizations wrote in the report. According to the nearly two dozen states that reported pediatric hospitalizations, 0.1% to 1.9% of all child COVID-19 cases resulted in hospitalization.

However, the two organizations warned that there is an urgent need to collect more data on long-term impacts of the pandemic on children, "including ways the virus may harm the long-term physical health of infected children, as well as its emotional and mental health effects."

-ABC News’ Arielle Mitropoulos

According to federal data, nearly 56,000 patients are now hospitalized with COVID-19 across the U.S., marking the highest number of patients receiving care since February.

Ninety-one percent of Americans are now living in high (a seven-day new case rate ≥100) or substantial (a seven-day new case rate between 50-99.99) community transmission in the last week.

Seven states -- Alabama, Arkansas, Arizona, Delaware, Florida, Louisiana and South Carolina -- have high or substantial community transmission in every county.

Louisiana, Arkansas, Florida, Missouri, and Alabama currently have the nation's highest case rates, followed by Mississippi, Texas, and Oklahoma.

-ABC News’ Arielle Mitropoulos

In Texas, the demand for vaccines is skyrocketing. The number of daily doses has jumped from about 44,000 (just after the 4th of July) to 73,000 as of Monday, said Chris Van Duesen, spokesperson for the state’s Department of State Health Services.

National Institutes of Health director Francis Collins told CNN Tuesday the data is "tipping" toward showing how the delta variant is more serious for children than past variants.

Collins listed studies from Singapore, Scotland and Canada that "certainly tilts the balance in that direction" but made clear that more data is needed.

Collins also added that part of the reason the U.S. is seeing more children in hospitals is because they're part of the unvaccinated population and he doesn't want to "overstate the confidence."

-ABC News’ Cheyenne Haslett

Mississippi is facing "a phenomenal increase in daily reported cases of COVID, and this is entirely attributable to the delta variant, which is sweeping over Mississippi like a tsunami," state health officer Dr. Thomas Dobbs said Thursday.

Dobbs said 97% of new cases are among the unvaccinated, and that 89% of hospitalizations and 85% of deaths are unvaccinated.

Dobbs pleaded with the public to get vaccinated, stressing that the unvaccinated population is driving the current surge, but that vulnerable, vaccinated people are suffering the fallout.

"There is going to be some collateral damage, unfortunately, even folks who've done everything they can to protect themselves," Dobbs said.

"The minority of folks who are vaccinated and hospitalized are overrepresented by the older and those with weaker immune system, so we're seeing a pretty dramatic spillover effect from the transmission in the community to more vulnerable parts of our population," he said.

-ABC News' Soorin Kim