Over 6 million cases of COVID-19 in children have been reported in the United States this year, with 287,000 cases added just in the past four weeks, according to a joint report released on Monday by the American Academy of Pediatrics (AAP) and the Children's Hospital Association. 

The AAP said it was urgent to collect more age-specific data to assess the severity of illness related to new coronavirus variants as well as potential longer-term effects on the physical, mental and social well-being of children and youth.

Child COVID-19 cases in the U.S., according to the report, are far higher than a year ago, when 24,000 cases had been reported as of July 15, 2021.

It also pointed out shortage of COVID-19 tests during Omicron variant surges and the increasing use of COVID-19 home tests that likely led to undercounting of cases.

"Vaccines and boosters are our best hope to move beyond the pandemic," said AAP on Twitter. 

Over 13.9 million children in the U.S. have tested positive for COVID-19 since the pandemic began, representing 18.6 percent of all cases.

(With input from Xinhua)