The Centers for Disease Control and Prevention has sounded the alarm about a mysterious rise in hepatitis infections among young children.

The agency said that it will investigate the infections after releasing a report Friday detailing a rash of nine severe cases in Alabama. The agency ruled out COVID-19 as a cause of the cases, which were confirmed in the state from October to February. In the report, the CDC said that three of the nine hepatitis patients, who ranged in age from 1 month to 6 years old, developed acute liver failure. Two of them got so severely ill they required liver transplantation.


Symptoms of hepatitis include fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, and jaundice, which causes skin and the whites of the eyes to turn yellow. The most common symptoms among the Alabama patients were vomiting and diarrhea, with some also experiencing upper respiratory symptoms.

The origin of the infections, which have also been reported in six other states, is unknown. But researchers reported that all of the children tested positive for adenovirus infection, which is not typically a cause of hepatitis in otherwise healthy children. Adenovirus usually brings along cold- or flu-like symptoms.

The children in Alabama had no underlying health conditions, no history of COVID-19 infection or vaccination, and all lived in separate parts of the state, suggesting the cases were unrelated. Scientists additionally ruled out hepatitis viruses A, B, and C, and several other conditions that typically cause hepatitis and liver infections.

“CDC is monitoring the situation closely to understand the possible cause of illness and identify potential efforts to prevent or mitigate illness. Enhanced surveillance is underway in coordination with jurisdictional public health partners,” the agency reported.

The agency issued an alert to healthcare providers last week to be on the lookout for symptoms and to report suspected cases to their local and state health departments. The CDC also acknowledged that the total case count in the U.S. could be an underestimate due to a lack of reporting. After the cases were detected in Alabama, the state put out a call for providers to inform health officials of new cases, but no new reports have come in.

“CDC is working with state health departments to see if there are additional U.S. cases, and what may be causing these cases,” the agency said last week. “At this time, we believe adenovirus may be the cause for these reported cases, but investigators are still learning more.”


The mysterious hepatitis outbreak is global. The World Health Organization reported last week that about 170 cases have been confirmed in 11 European cases, with many of the children afflicted under 10.

“What is particularly unusual is that the majority of these children were previously healthy,” Dr. Philippa Easterbrook, a WHO official who monitors hepatitis, said on Thursday.

The WHO has initiated a far-reaching investigation of the new cases, imploring physicians in different countries to alert the health body when they identify new patients.