The number of children under investigation for unexplained, severe liver inflammation has increased to 180, the Centers for Disease Control and Prevention said Wednesday.
That's up from 109 suspected cases reported earlier this month. The new cases are from 36 states and U.S. territories. Most patients are under age 5.
Despite the increase, the agency said that there is no indication the number of hepatitis cases are truly rising. Investigators have been reviewing cases reported over the past seven months. Hepatitis refers to liver inflammation, which can have many causes.
Most "involve patients that are just now being reported, rather than new cases of hepatitis," the CDC said in a media statement Wednesday.
All, including five deaths, remain under investigation. The CDC also lowered the percentage of children who have been sick enough to receive a liver transplant, from nearly 15 percent to 9 percent.
The cause remains unknown, but investigators suspect an adenovirus may play a role.
The virus has been detected in about half of the cases under investigation in the U.S., as well as many such cases in the United Kingdom.
Adenoviruses can often lead to relatively mild stomach bugs, but don’t usually cause severe liver inflammation.
These unusual hepatitis cases have increased as Covid cases in general have risen, particularly among young children.
While there is no evidence that the coronavirus is directly causing hepatitis in children, investigators are now looking at whether a previous case of Covid may be triggering abnormal responses in kids' immune systems.
Doctors overwhelmingly want to assure parents that, while alarming, these cases are rare.
"We encourage parents and caregivers to be aware of the symptoms of hepatitis — particularly jaundice, which is a yellowing of the skin or eyes," the CDC wrote.
A majority of patients also had nausea and vomiting, as well as fatigue and loss of appetite.