Among them, 14% needed transplants and five children have died.
Almost all children, more than 90%, had to be hospitalized.
Dr. Jay Butler, the CDC’s deputy director of infectious diseases, stressed that research, a partnership between the CDC and state health departments, is an evolving situation. Not all cases of hepatitis that are being studied now can ultimately be caused by the same thing.
“We’re launching a broad network to help broaden our understanding,” Butler said.
It is not yet clear what is driving these cases in young children. Butler said some of the common causes of viral hepatitis have been considered, but none were found. Adenovirus has been detected in more than 50% of cases, although its role is unclear.
Early reports of hepatitis
The agency asked doctors and public health officials to warn them if they had similar cases of children under 10 with elevated liver enzymes and no apparent explanation for their hepatitis since October 2021.
Since then, state health departments have worked with pediatric specialists in their states to identify possible cases. The figures shared at Friday’s news conference are the first national look at cases in the United States.
The states and territories where the cases are being investigated are: Alabama, Arizona, California, Colorado, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Louisiana, Michigan, Minnesota, Missouri, North Carolina, North Dakota, Nebraska , New York, Ohio, Pennsylvania, Puerto Rico, Tennessee, Texas, Washington, and Wisconsin.
Most children were healthy when they developed symptoms that included fatigue, loss of appetite, vomiting, diarrhea, abdominal pain, dark urine, light-colored, yellowish stools on the skin and eyes, a sign that caused jaundice.
Unusually severe liver inflammation
Pediatric gastroenterologist Dr. Heli Bhatt of the University of Minnesota Medical Center has treated two children who are part of the CDC’s research. One, a 2-year-old boy from South Dakota, had a liver transplant on Friday morning.
Bhatt says liver failure in children is “super rare.” And even before scientists began tracking this outbreak, half of the cases were never reported.
Doctors who have cared for these children say their cases stood out.
“Even during the first case, I thought it was weird,” says Dr. Markus Buchfellner, a pediatric infectious disease specialist at the University of Alabama at Birmingham, where they began seeing cases in October.
“And then when the second one came in was when I said okay, we need to talk to someone about it.” He contacted senior doctors in his department who contacted the state health department and the CDC.
Buchfellner says the cases stood out because his liver inflammation was so severe.
Sometimes common viruses like Epstein-Barr or even SARS-CoV2 will slightly increase a child’s liver enzymes, indicating what Buchfellner calls “small pieces of hepatitis,” but children usually recover as they go. that your body is fighting the infection.
“But it’s very rare to see a child who is healthy with the amount of liver damage these children had,” he said.
Initially, The UAB saw nine children with unexplained hepatitis and all nine tested positive for adenovirus in their blood.
Since these cases were first reported, two more children have been identified in Alabama and their cases are under investigation, bringing the state’s total to 11 cases under investigation, Dr. Wes said. Stubblefield, a medical officer in the northern and northeastern districts of Alabama in an interview. with CNN.
There are about 100 different types of adenovirus. About 50 of them are known to infect humans, so they needed a closer look at the virus to try to find out if all the children had the same thing.
When the researchers tried to read the adenovirus genes in infected children, only five had enough genetic material to obtain a complete sequence. In all five, the virus was a particular type of adenovirus called adenovirus 41, which usually causes diarrhea and vomiting in children, sometimes with congestion or cough, but has never before been associated with liver failure.
Tracks from the UK
In addition to the CDC briefing, researchers at the UK Health Safety Agency released a new technical briefing on Friday with an update on their hepatitis research. Of 163 cases, 126 patients were tested for adenovirus and 91, or 72%, were positive for this pathogen.
Researchers have tried to sequence the entire genome of an adenovirus from one of the patients, but have not yet been able to obtain a sample with enough virus to do so. Of the 18 cases in which they were able to partially sequence the genome of the virus, all 18 were adenovirus 41F, the same as found in US cases.
Many have wondered if the cases may be related in any way to SARS-CoV2, the virus that causes Covid-19.
Researchers in the UK say they are still studying this possibility, but only 24 of 132 patients tested – 18% – had detected SARS-CoV2.
The report says they do not rule out any role for a Covid-19 infection in these cases. Perhaps a previous Covid-19 infection somehow prepared the immune system to make these children unusually susceptible, or perhaps a co-infection of the two viruses together overwhelms the liver. Researchers also want to know if hepatitis may be part of some kind of syndrome that affects children after a SARS-CoV2 infection, as is the case with multisystem inflammatory syndrome of rare complications in children, or MIS-C.
Another working theory of researchers in the UK is that there may be some kind of disproportionate or irregular immune response in these children, perhaps because they were protected more than usual during the pandemic.
Another theory is that adenovirus may have always caused liver failure in a small percentage of infected children, and these rare cases only come to light because it is causing an exceptionally large wave of infections.
And researchers in the UK say they are still testing for drugs, toxins or perhaps environmental exposure, although some sort of infection is likely to be the cause.
Classification of the role of adenovirus 41
Another thing that baffles doctors, says Buchfellner, is that they found adenovirus in blood samples, but not in liver tissue samples taken during biopsies. of Alabama patients.
“All nine have liver biopsies that showed a lot of inflammation. And hepatitis. But we didn’t find the virus in the liver. We only found the virus in the blood,” he said.
The case of Bhatt, a South Dakota child, was also positive for adenovirus in the blood, but not in the liver.
If this adenovirus 41 is somehow responsible in these cases, and this is still very important, Buchfellner says he doesn’t know why it would only appear in the blood, but not in the heavily damaged liver tissue, but he has some theories. .
“Maybe the liver is clearing the virus before it has cleared into the bloodstream,” he said. “And so, when the liver is damaged, and we do the biopsy, the immune system has already removed the virus from the liver. And what’s left is just inflammation.”
His second theory, he says, is that the virus itself may not be responsible for liver damage, but the immune system may overreact when it tries to fight the virus and end up damaging the liver.
Adenovirus infections are common, so perhaps finding the virus in some of these patients is just a coincidence. “We are not 100% sure that this is just this adenovirus. Much remains to be seen, “says Bhatt.
“We’re still telling our at least our families here in Alabama and I would encourage other families alike not to be too worried about it yet.” said Buchfellner. “I mean, at the end of the day, this is still a pretty weird phenomenon,” he said.
Buchfellner says adnoviruses are commonly transmitted through kindergartens and schools. They usually don’t cause anything worse than something that feels like a stomach flu for a few days.
“It has been around for a long time and will continue to circulate. And in total, we only have around 200 cases that have been reported worldwide. So this is not a Covid pandemic situation in which everyone is really worried about that, “he said.
This is breaking news and will be updated.