Children play on a tractor at a Pumpkinfest in Lincolnshire, Illinois, the United States, on Oct. 17, 2020. (Photo by Joel Lerner/Xinhua)

Nearly 1.2 million children in the United States have been diagnosed with COVID-19 since the onset of the pandemic, according to the latest data of the American Academy of Pediatrics (AAP) and the Children's Hospital Association.

A total of 144,145 new child COVID-19 cases were reported the past week from Nov. 12 to 19, a 28 percent increase in child COVID-19 cases in the country, according to the AAP.

The number of new child COVID-19 cases is by far the highest weekly increase since the pandemic began, said the AAP.

Children now account for more than 11 percent of all confirmed coronavirus cases in the United States.

The overall rate was 1,573 cases per 100,000 children in the population, according to the APP report.

Children accounted for 1.2 percent to 3.1 percent of total reported hospitalizations, and 0 to 0.23 percent of all COVID-19 deaths, said the report.

"At this time, it 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.