The deaths of five children and what could be an unusual cluster of more than 100 cases of hepatitis in young children in the United States are under investigation by the Centers for Disease Control and Prevention, the agency said Friday.
The CDC said it is examining cases involving 109 children in 25 states and territories who have had or have what the agency calls “hepatitis of unknown cause.”
Dr. Jay Butler, deputy director of infectious diseases at the CDC, said most of the children have made a full recovery. But more than 90 percent were hospitalized, 14 percent received liver transplants and more than half had adenovirus infections, he said.
The CDC and experts abroad are exploring whether a type of adenovirus, a common virus that causes intestinal symptoms like vomiting and diarrhea, could be a factor in these cases. But the agency did not determine a cause for the cases or a common link between them all and cautioned against drawing conclusions.
Dr. Butler called it “an evolving situation” at a news conference on Friday. He later added: “It is important to remember that severe hepatitis in children is rare, even with the potential increase in cases that we are reporting today.”
An inflammation of the liver usually caused by a virus, hepatitis carries a number of complicating factors, side effects and stigma.
Hepatitis and liver failure are uncommon occurrences in young children, especially healthy children, and so far the actual number of hepatitis cases in the United States is no higher than the number normally observed.
The agency did not provide details about the children who died or where those deaths occurred.
The UK is investigating a much larger number – more than 160 cases – of young children who have had or have had hepatitis recently.
Hepatitis, an infection of the liver, usually occurs in adults and can be caused by viruses — which respond to drug treatment — or by alcoholism, some medications, or autoimmune conditions. Symptoms include yellowing of the skin and eyes, nausea, and abdominal pain.
The Doctor. Butler also said there was no evidence so far that a Covid-19 infection or the Covid vaccine was linked to US cases. The World Health Organization also said this week that the “vast majority” of children were not vaccinated in the cases it analyzed.
The alarm started two weeks ago, when the CDC issued an alert, citing nine cases of hepatitis among young children in Alabama that began in the fall of this year. All had evidence of adenovirus infection. Their average age was 2.
The problem for the CDC is determining whether adenovirus is a cause or an innocent bystander, said Dr. Butler. Doctors typically don’t test children for adenovirus infections — it’s not a notifiable disease in the United States — making it difficult to unravel causes and effects. He urged doctors to consider adenovirus testing if children are sick with certain symptoms.
It is not known how likely nine children tested were at random to have adenovirus infections. The virus is also seasonal, and fall and winter, when Alabama children were sick, is adenovirus season.
To further complicate the situation, when the children were evaluated, the amount of virus, if found, was very low.
“We are working hard to determine the cause,” said Dr. Butler. Because hepatitis in children remains “a rare event,” he said, the search is difficult.
Other possibilities include environmental exposures, including exposures to animals or an immune reaction, with a reaction to an adenovirus “at the top of the list,” Butler said.
“We are casting a wide net,” he said.