According to a new report from the American Academy of Pediatrics (AAP) on Wednesday, Aug. 4, the number of children infected with COVID-19 has increased fivefold since the end of June, with a “substantial” 84% increase in the last week alone. In addition, numerous states are reporting increases in child hospitalizations amid the ongoing delta surge.

AAP report shows that 72,000 new infections were recorded in the seven days leading up to July 29, up from 39,000 the week before.

Last week, major children’s hospitals in Alabama, Arkansas, Louisiana, and Florida—all of which have seen a spike in hospitalizations—all claimed they had more children in their care than at any other time throughout the pandemic, as reported by Forbes.

The study says that AAP also collaborated with Children’s Hospitals of America to help gather and exchange data on pediatric cases of the virus, which accounted for only 14.3% of the total cumulative cases. For the week ending July 29, that percentage increased to 19%. 4.2 million children have tested positive for the virus since the outbreak began.

Hospitalization rates among children peaked at 2.1 per 100,000 in January, according to the last recent report from the Centers for Disease Control and Prevention (CDC), released in early June. However, the AAP notes the number of hospitalizations remained stable throughout the pandemic, with children accounting for between 1.3% and 3.5% of hospitalizations, depending on the state.

Overall, children who get COVID-19 have a low risk of death and hospitalization. Since the pandemic began, over 520 children have died from COVID-19 (0.08% of the 612,000 overall deaths). However, because it “occurs in all age groups,” the CDC emphasizes severe disease can still affect children.

Dr. Yvonne Maldonado, chair of the AAP committee on infectious diseases and chief of the division of infectious diseases in the Department of Pediatrics at Stanford Medicine, told CNN, “That’s high and considering the fact that we are vaccinated now, what that’s telling us is that unvaccinated people are getting infected in higher numbers because the virus is more infectious with the Delta variant.”

Our sense is because kids can’t get vaccinated, parents should clearly be vaccinated themselves, and if their kids are 12 and older, they should be vaccinated as well,” Maldonado said.

Experts have created various explanations for why child hospitalizations are on the rise. Many point to the trend of younger people accounting for a more significant proportion of new cases.