A new report from the Centers for Disease Control and Prevention appeared to rule out Covid as a factor in the mysterious cases of severe hepatitis in children, at least in the nine confirmed cases in Alabama.
The report, published Friday, details the Alabama cases, which first drew attention to the liver illnesses in the United States. Last week, the CDC put out an alert advising doctors across the country to be on the lookout for unusual hepatitis cases.
More than a dozen other cases are now being investigated in eight other states: One in Delaware, another in Louisiana, three in Illinois, two in North Carolina and four in Wisconsin.
Friday, the Tennessee Department of Health said that it has six cases. And state health departments in Georgia and New York also said they are investigating "a handful" of potential cases.
At least three children have needed liver transplants, and officials in Wisconsin are investigating the death of one child.
According to the new report, none of the Alabama children tested positive for Covid when they were admitted to the hospital, and none had a previously documented case of the illness. None had received a Covid vaccine.
The children — seven girls and two boys — ranged in age from 1 month to 6 years old, with a median age of 2, and all were diagnosed with hepatitis from October to February. On Feb. 1, a statewide alert went out to doctors, but no other patients were identified.
The patients all hailed from different regions of Alabama — suggesting they had no connection to one another — though they were all treated at Children's of Alabama, a hospital in Birmingham.
Study co-author Dr. Markus Buchfellner, a pediatric infectious diseases fellow at the University of Alabama at Birmingham, was the first to notice the unusual pattern of unexplained hepatitis in these children.
"When we see a healthy child who comes to the hospital and has signs and symptoms of hepatitis, a virus is the most common cause," Buchfellner told NBC News.
All were previously healthy children, without any underlying health problems. But none tested positive for the usual viruses that cause hepatitis, including hepatitis type A, B and C viruses. Several other causes of hepatitis in children were also ruled out.
Six kids showed signs of past infections with the Epstein-Barr virus, but it remains unclear whether reactivation of these old infections could play a role.
Symptoms of liver problems in children
All nine children did, however, test positive for an adenovirus, a virus typically associated with cold-like symptoms. Five of the nine tested positive for a specific type: adenovirus 41.
While adenovirus 41 has not been proven as the cause of these cases, Buchfellner said it could be a key clue.
"That's one of the big reasons for publishing our case series, talking to the CDC and investigating this to see if there is truly a link between adenovirus and hepatitis," he said.
According to the report, the specific virus is a common cause of gastrointestinal illness in children, with symptoms including:
- respiratory symptoms
Seven patients reported vomiting, six reported diarrhea and three reported upper respiratory symptoms.
Symptoms linked to liver problems were also common, including:
- yellowing of the white parts of the eyes, seen in eight children
- an enlarged liver, seen in six.
- One child had encephalopathy, a kind of altered brain function.
Also puzzling: Doctors performed liver biopsies on some of the patients but did not find adenovirus particles in any of them.
Buchfellner said in general, viruses that cause hepatitis can typically be detected in liver tissue, because those viruses attack the organ.
Why the virus was found in the patients' blood but not necessarily their livers is an ongoing area of investigation.
"Some of my theories are that it could be something to do with the specimens we sent not having the virus in it and the timing of the biopsies," Buchfellner said. "This is one of the big questions we are hoping to answer by looking at affected liver tissue from other patients across the country."
Adenovirus type 41 is primarily spread from fecal matter, once again highlighting the importance of proper hand-washing.
The World Health Organization said about 170 cases of severe, unexplained hepatitis in children have been reported in 16 countries.
Most of those patients are in the United Kingdom, where incidence of adenovirus has risen recently, the head of the WHO/Europe high-threat pathogens team, Richard Pebody, said Thursday during an online question-and-answer session.
The WHO has alerted physicians worldwide to be on the lookout for such unusual cases of hepatitis.