From that article - "No link has been detected to Covid vaccines, with most of the patients not yet eligible to receive them."
From another article - "Second, there’s no indication that any of the kids with hepatitis have received the J&J vaccine. It’s not authorized for use in children in the U.S., and the company confirmed to FactCheck.org that it’s not authorized for kids anywhere in the world." -
Pediatric Hepatitis Cases May Be Linked to Adenovirus, No Connection to COVID-19 Vaccination - FactCheck.org
The elephant in the room type of question seems easy enough to confirm directly without having to infer that the kids were not vaccinated because they were "not yet eligible" or "there was no indication". Be a fucking journalist. Go ask the parents if the kids were vaccinated. This is odd.