So far, at least 18 cases have been reported in at least four states — and dozens more in Europe.
The latest clinical details shared by the CDC on Friday come from Alabama, where the first cases were found. Clinical data was analyzed from a total of nine patients admitted to a children’s hospital after October 1, 2021.
The patients came from different parts of the state with no epidemiological links. All were considered generally healthy, with no significant co-morbidities and no immune system weakness. The median age was approximately three years, ranging from less than 2 years old to older than 5 years.
Vomiting and diarrhea were the most common symptoms in patients before admission, and some also had upper respiratory tract symptoms. On admission, most had an enlarged liver, jaundice and yellowing of the eyes.
All patients received negative test results for hepatitis viruses A, B, and C, and several other causes of pediatric hepatitis and infections were excluded. But in all patients adenovirus was detected.
Of the nine patients in Alabama, six had positive test results for the Epstein-Barr virus, which were determined to be the result of previous infections. Other viruses detected were enterovirus/rhinovirus, metapneumovirus, respiratory syncytial virus and human coronavirus OC43.
No patient had a documented history of previous Covid-19 infection.
Three patients developed acute liver failure, two of whom underwent liver transplantation. The CDC reports that all patients have recovered or are recovering, including transplant recipients.
Hepatitis is inflammation of the liver, a vital organ that processes nutrients, filters the blood and helps fight infection. When the liver is inflamed or damaged, its function can be compromised.
Usually, hepatitis is caused by a virus, and adenoviruses are a common type of virus that is spread from person to person and can cause a range of mild to more serious illnesses. But these viruses are rarely reported as a cause of severe hepatitis in healthy people.
Adenovirus is recognized as a cause of hepatitis in immunocompromised children, but may be an “under-recognized contributor to liver damage in healthy children,” according to the CDC. It is mainly spread from the stool to the mouth.
There is no vaccine against adenoviruses in children. Adenoviruses tend to linger on surfaces, and alcohol-based hand sanitizers don’t work well against them, according to Dr. Ashlesha Kaushik, a spokesperson for the American Academy of Pediatrics.
“Washing your hands thoroughly with soap and water is best,” Kaushik said. “Keep your distance from anyone sick from coughing and sneezing, and teach your kids to cough or sneeze into their sleeve.”
CNN’s Jacqueline Howard, Brenda Goodman, Michael Nedelman, John Bonifield and Jen Christensen contributed to this report.