Studies Shed Light On Rare Hepatitis That Sickened NY Kids

NEW YORK — Scientists think they may know more about the origins of an unexplained outbreak of severe hepatitis that has sickened children in New York.

Researchers found severe hepatitis infections, which causes a liver inflammation, occurred at the same time many of the children were sick with multiple other viruses, including adeno-associated virus type 2, or AAV2, according to a small study of American children published last week in the journal Nature.

To replicate, it needs one or more “helper” viruses, the researchers said. The findings, while speculative, “suggest that the severity of the disease is related to co-infections involving AAV2 and one or more helper viruses,” the researchers wrote.

Since the first cases were reported in 2021, at least 13 young children have died of severe hepatitis illnesses in the United States and 22 have needed liver transplants, according to data from the Centers for Disease Control and Prevention that was last updated in August.

The researchers’ findings are consistent with those in two British studies, and could influence how the illnesses that have flummoxed medical experts are treated.

CDC data updated last week showed 391 suspected cases of the rare form of hepatitis in children 10 and younger under investigation in 46 states. The agency doesn’t release the specific number of cases in each state for privacy reasons.

In New York, the state Department of Health said it's working with local and federal public health authorities, including the CDC, to investigate pediatric hepatitis cases in children under 10 to see if any may be related to the illness that has been reported in Europe and the United States.

Health experts believe extended COVID-19 lockdowns and social distancing left many children vulnerable to common bugs such as common colds, influenza and RSV.

The timing of the AAV2 outbreak with the loosening of pandemic restrictions in 2021 is similarly suspect, Dr. Charles Chiu, an infectious disease specialist and microbiologist at the University of California, San Francisco, and one of the authors of the study, told The New York Times.

“That may have resulted in a population that was highly vulnerable to getting infected with multiple viral infections,” he said.

“Children were suddenly exposed to a barrage of viruses after lockdowns or had poorly trained immune systems that led to an increased susceptibility to otherwise harmless viruses,” Dr. Frank Tacke, a gastroenterologist from Germany who was not involved with the research, wrote in a commentary accompanying the study.

More research is needed, Tacke said, but “the fact that three independent groups found this from different areas of the world actually makes it really convincing.”

Among questions yet to be answered are whether AAV2 infections are a precursor to severe hepatitis, play a more casual role are coincidental. It could be the cases stem from a previously unknown virus, according to experts.

“If AAV2 directly caused hepatitis, one would expect more cases to have been reported,” Tacke wrote in his commentary, according to a report from CNN.

The first known cases in the hepatitis outbreak were reported in Alabama in October 2021. Five children had significant liver illnesses, including some with liver failure, but tested negative for the more common hepatitis A, B and C viruses, but positive for adenovirus, a common virus that typically causes cold- and flu-like illnesses and, more rarely, stomach and intestinal problems, according to the CDC.

From April to July 2022 more than 1,000 children in 35 countries have been diagnosed with the severe acute hepatitis illnesses. Nearly 50 children needed liver transplants, and 22 died, according to data from the World Health Organization.