Ninety-seven thousand US children tested positive for coronavirus in the second half of July - weeks before schools and universities reopen.
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