Nearly 48,000 child Covid-19 cases were reported in the US in the week ending December 22, the third consecutive weekly rise in child cases, according to the latest report by the American Academy of Pediatrics (AAP) and the Children's Hospital Association.

Nearly 15.2 million children in the country had tested positive for Covid-19 since the onset of the pandemic, Xinhua news agency reported.

Nearly 165,000 of these cases had been added in the past four weeks, and the reported cases were likely a "substantial undercount" of Covid-19 cases among children, said the report.

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, the report added.

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.