The number of probable cases of children with acute severe hepatitis in Japan has reached seven, the health ministry said Friday.

The tally includes the nation’s first case reported April 25, as well as another two confirmed on April 28, and four more reported Friday. The patients are all 16 years old or younger and the ministry has withheld their exact age, location and sex for privacy reasons.

One patient has tested positive for the coronavirus, and one patient tested positive for adenovirus Type 1. The health ministry declined to disclose whether these are two separate people or one person who contracted both viruses. None of the seven has had a liver transplant, the ministry said.