Until recently, a prevailing theory about the severe hepatitis cases popping up in children suggested that an adenovirus was probably to blame.
Since April, many young kids with dangerous liver inflammation have tested positive for adenovirus 41, which typically causes coldlike illness or an upset stomach. But two studies released this month, which have not yet been peer-reviewed, outlined another theory: Some children may have been infected with an adeno-associated virus, which uses a second helper virus to replicate.
Researchers from Scotland and England detected one particular adeno-associated virus, called AAV2, in the blood and livers of U.K. children with severe hepatitis. The researchers suggested that some kids may have been co-infected with AAV2 and another virus like adenovirus 41 — a combination that could result in liver failure. The studies also identified a genetic marker that might put children at higher risk of this outcome.
But doctors aren’t sure if the cases themselves are novel. Even before this year, many pediatric hepatitis cases were a mystery — between 30% and 50% of such cases are from unknown causes, according to the Centers for Disease Control and Prevention.
“Liver failure always appropriately sounds horrific and should never happen, but it does happen, and it does happen without us often knowing the cause in children,” said Saul Karpen, a gastroenterology professor at the Emory University School of Medicine. “We do all the right studies. We can’t figure it out.”
Karpen said that approximately half of the acute hepatitis cases that typically show up to his hospital, Children’s Healthcare of Atlanta, have no clear origin. Around 10% of those cases progress to severe liver failure and can require a transplant, he estimated. In a recent editorial in the New England Journal of Medicine, Karpen called for more data to determine whether the recent cases are truly out of the ordinary.
In a report released earlier this month, the European CDC similarly said it is not clear whether the cases identified since April “are part of a true increase compared to the baseline rate.”
New insight into potential causes of this illness, then, might help address a longstanding medical mystery rather than a new one.
Are the recent hepatitis cases abnormal?
Since a spate of pediatric hepatitis cases sparked concern in the U.K. in April, the World Health Organization has detected more than 1,000 probable cases — including 22 deaths — across 35 countries.
Europe had recorded more than 500 cases as of Thursday, mostly among children 5 years old and younger. Around half of those patients recovered, but 94 remained under medical care and 22 received liver transplants. Three deaths have been reported in Europe, including a child in Ireland who died in May and another who died in Greece this month.
In the U.S., health officials were investigating more than 350 suspected cases of acute hepatitis in kids under 10 as of Wednesday, all of them recorded since October 2021.
But last month, the CDC said there was no sign that an increasing number of children were being hospitalized for hepatitis relative to rates before the Covid pandemic. From October 2021 to March 2022, the U.S. saw an average of 22 monthly hepatitis-related hospitalizations among children under 4, and 12 among children ages 5 to 11. The country recorded similar averages in 2019.
Some experts think hepatitis cases may have temporarily spiked once Covid restrictions lifted, because young children subsequently got exposed to viruses that their bodies hadn’t seen before.
Source: NBC HEALTH NEWS
