As of July 15, 4.09 million children in the United States have tested positive for COVID-19, according to the American Academy of Pediatrics (AAP). 

Moreover, after decreases in weekly reported cases over the past couple of months, the country began to see increases in cases in July, according to a report released by the AAP and the Children's Hospital Association.

Over 23,500 child cases were reported in the week ending July 15, according to the report. Children represented 14.2 percent of all COVID-19 cases in the country.

Children accounted for 1.3-3.6 percent of total reported hospitalizations in 23 states and New York City, and 0-0.26 percent of all COVID-19 deaths in 43 states, New York City, Puerto Rico and Guam, said the report.

"At this time, it still appears that severe illness due to COVID-19 is rare among children. However, there is an urgent need to collect more data on longer-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," the AAP said in the report.

Cases of COVID-19 in children in the U.S. have nearly doubled since late June, according to a CNN report.

Children under 12, who are not yet eligible to be vaccinated, get affected as the virus spreads among unvaccinated adults. Experts believe young children will pay the price if enough American adults do not get inoculated against the disease.

"It doesn't look like this virus is selectively targeting children," said Peter Hotez, professor and dean of Tropical Medicine at Baylor College of Medicine, in an interview with CNN. "It's just that so many unvaccinated individuals are getting Delta that children are getting swept up along with it."

COVID-19 cases, hospitalizations and deaths were all up double digits in recent weeks as the highly contagious Delta variant spread across the country. 

Delta accounts for approximately 83 percent of new COVID-19 cases in the country, according to Rochelle Walensky, director of the U.S. Centers for Disease Control and Prevention.