The cases have stumped experts, who are investigating a variety of potential causes. One leading hypothesis is that an adenovirus, a family of common viruses that typically cause flu- or cold-like symptoms, may be responsible, but many questions remain.
The revelation that Liviah’s case might be part of a larger phenomenon has galvanized her parents, who have started sharing their story in hopes of educating others about the key warning signs.
Due to the lack of documented adenovirus infection in all reported child hepatitis cases, a significant amount of effort is focused on investigating other potential causes. One possibility is that Covid-19, along with infection by another common virus – like adenovirus – may result in liver disease. In some patients, Covid-19 may hyper-stimulate the immune system and increase the odds that a subsequent viral infection could trigger damaging inflammation.
In light of these findings, the CDC is advising healthcare professionals to test for adenoviruses in pediatric patients diagnosed with hepatitis from unknown causes.
Alabama has reported that nine children under 10 had the rare condition, and a few suffered liver failure. Similar cases were reported in North Carolina, as well as in Britain and Israel.
Vomiting and diarrhea were the most common symptoms among patients before admission, with some also experiencing upper respiratory symptoms. At admission, most had an enlarged liver, along with jaundice and yellowing in the eyes.
All patients received negative test results for hepatitis viruses A, B, and C, and several other causes of pediatric hepatitis and infections were ruled out. But adenovirus was detected in all patients.
Laboratory investigations of the cases excluded viral hepatitis types A, B, C, D and E in all cases. Of the 13 cases reported by Scotland for which detailed information is available regarding testing, three tested positive for SARS-CoV-2 infection, five tested negative and two were documented to have had an infection in the three months before presentation. Eleven of these 13 cases had results for adenovirus testing and five tested positive.
Severe hepatitis in children is very rare and we don’t yet know what’s causing this highly unusual rise in cases. The leading theory is that it’s some kind of viral infection, perhaps even SARS-CoV-2, the coronavirus that causes COVID-19.
But how likely is it that these hepatitis cases are linked to COVID? Or is there a more likely cause to be found elsewhere?
More than 100 cases of severe hepatitis in children have been reported globally. What to know about symptoms, and how to spot signs that something is amiss.
But what isn’t adding up is the fact that an adenovirus infection is usually pretty mild. Although adenoviruses can cause hepatitis on rare occasions, this isn’t something they’re known for. One theory is that a mutated form of adenovirus could be circulating, which would explain why reactions are more severe than usual.
While acute hepatitis is not unheard of in children, these latest figures are unprecedented, and so far, only partly explained.
One suspect is infection by an adenovirus. According to the UK Health Security Agency, adenovirus was the most common pathogen found in 40 of 53 confirmed cases tested in the UK.
But the WHO said in its latest report on the cases that while adenovirus is currently one hypothesis as the underlying cause, “it does not fully explain the severity of the clinical picture”. The strain of adenovirus, known as type 41, seen in many of the children has not previously been linked to severe hepatitis.
No one knows exactly why hundreds of kids have shown up with hepatitis, but investigators have some ideas.
It’s also possible that children’s immune systems, weakened after months of social distancing during the Covid-19 pandemic, are now more vulnerable to diseases like hepatitis, Imperial College London liver researcher Simon Taylor-Robinson told Reuters.
The C.D.C. issued an alert after clusters of severe hepatitis cases popped up among children around the globe. What signs should parents watch out for?
Testing for viruses has shown SARS-CoV-2 (which causes Covid) in some children; others have had adenovirus infection, and some showed evidence of both viruses on testing. One hypothesis raised by the Scottish investigators is that perhaps the illnesses are more severe because they are infecting “immunologically naive” children who have been sheltered throughout the Covid pandemic.