The figures, taken from the American Academy of Pediatrics from July 16 to 30, come as the country tops five million cases - 338,000 of which are children - and over 162,000 deaths.
As some schools re-open for face-to-face classes this month, Dr Tina Hartert, of Vanderbilt University, said increased testing of kids is key to understanding their role in transmitting the killer bug.
The doctor is leading a government-funded study which has seen 2,000 families receive DIY testing kits.
"The kits are shipped to the families, they are taught how to collect these samples, and then the samples are sent back by the families to a central repository," she told CBS News.
It was initially believed children were less susceptible to the virus - however, at least 25 kids have died in the US in July from Covid-19.
It's left teachers and school bosses desperately looking for solutions on how to follow restrictions while educating pupils.
Some universities are also grappling with safely reopening campuses, with new restrictions including banning parties, road trips and outside visitors.
