The [AAP and Children's Hospital Association] said 70,630 new child cases were reported from August 20 through September 3. This is a 16% increase in child cases over two weeks, bringing up the total to at least 513,415 cases, the groups said in their weekly report on pediatric coronavirus cases. … Children represent nearly 10% of all reported cases in the US, according to the report. The child cases are likely underreported because the tally relies on state data that is inconsistently collected.