Washington, Dec 7 : Over 15 million children in the US have tested positive for Covid-19 since the onset of the pandemic in early 2020, according to the latest report by the American Academy of Pediatrics (AAP) and the Children's Hospital Association. About 114,000 of these cases have been added in the past four weeks, Xinhua news agency quoted the report as saying. A total of 28,600 child Covid-19 cases were reported in the latest week ending December 1, said the report, adding that cases are likely a substantial undercount of the ones among children. There is a need to collect more age-specific data to assess the severity of illness related to new variants as well as potential longer-term effects, said the report. "It is important to recognise there are immediate effects of the pandemic on children's health, but importantly we need to identify and address the long-lasting impacts on the physical, mental, and social well-being of this generation of children and youth," said the AAP. /IANS