The Centers for Disease Control and Prevention is investigating 109 childhood cases of a mysterious form of hepatitis, including five reported deaths, the agency said Friday.
“Researchers both here and abroad and around the world are working hard to determine the cause,” said Jay Butler, deputy director for infectious diseases at the CDC.
90% of cases have involved hospitalization, with 14% requiring liver transplants. Most have fully recovered.
The CDC issued a health alert last month notifying doctors and public health authorities to be on the lookout for similar cases, and began examining case histories dating back to Oct. 1, 2021.
More than half of the cases tested positive for adenovirus 41, a virus normally associated with gastroenteritis but not hepatitis in otherwise healthy children.
“Because of the link to adenovirus, I would call it top of the list of viruses of interest,” Butler said.
“But we don’t know if it’s the adenovirus itself that’s causing the cases, or if there’s an immune reaction to this particular strain of adenovirus.”
Environmental factors, such as the presence of animals in the home, as well as whether other pathogens, such as COVID-19may have played a role.
Adenovirus cases could also be recovering after COVID lockdowns stopped the spread for a few years, or the adenovirus could have become a newer, more dangerous strain.
But the CDC has said it doesn’t think COVID vaccines are to blame.
Nine cases in Alabama that were investigated in depth were among children with an average age of two, too young for COVID vaccination.
Thursday, North Dakota became the latest in a growing number of states investigating the mystery illness. The Grand Forks County boy is recovering at home after a brief hospital stay, officials with the North Dakota Department of Health said.
The cases have no known connection, although a link to a virus that can cause colds is being investigated. Several cases have been reported in Minnesota.
More than two dozen cases have been reported across the country, including at least four in Wisconsin last month. A boy in Wisconsin needed a liver transplant and another died.
Symptoms may include cold-like symptoms, fever, sore throat, pneumonia, diarrhea, or conjunctivitis.
In the past week, Three children in Indonesia died of the illness
Associated Press contributed to this report.