WASHINGTON, Dec. 15 (Xinhua) -- Nearly 1,640,000 children in the United States have been diagnosed with COVID-19 since the onset of the pandemic, representing 12.2 percent of the caseload nationwide, according to a new joint report from the American Academy of Pediatrics (AAP) and the Children's Hospital Association.

A total of 178,823 new child COVID-19 cases were reported over the past week from Dec. 3 to 10, the highest weekly increase since the pandemic began, said the report published Thursday.

There was a 23-percent increase in child COVID-19 cases over the two weeks from Nov. 26 to Dec. 10, it said.

The overall rate was 2,179 cases per 100,000 children in the population, said the report.

Children accounted for 1.2 percent to 2.9 percent of total reported hospitalizations, and 0 percent to 0.21 percent of all COVID-19 deaths, it said.

Out of the 49 states, New York City, the District of Columbia, Puerto Rico and Guam which provided age distribution of reported COVID-19 cases, 11 states reported over 50,000 child cases, 13 states said at least 15 percent of their cases were children, whereas 10 states reported more than 3,500 cases per 100,000 children, it said.

"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 report said.

In her latest statement, AAP President Sally Goza urged vaccine makers to "include younger children in their trials as it becomes safe to do so," to make sure that "children of all ages and diverse populations can return safely to school in the fall."

"How long that (COVID-19) tunnel will be depends on Americans practicing the public health measures that have been proven to reduce the spread of the virus: social distance, wear masks, avoid crowds, wash hands, and get the vaccine when it becomes available," she added.

The United States on Monday started its COVID-19 vaccine rollout nationwide. The country has so far registered more than 16.7 million cases with over 303,000 related deaths, according to the real-time count kept by Johns Hopkins University.e virus and 94,784 are being checked.