Meanwhile Israel has detected 12 cases and in Europe, nine countries have so far reported roughly 30 cases – including in Ireland, Spain and Denmark. Of these, four children have required transplants, and most have needed hospitalisation. The youngest was only one month old.
Investigators across the globe are rushing to explain the mystery, hunting for potential infections and analyzing the children’s immune systems, genetics, diets and recent movements. In the Eurosurveillance report describing Scotland’s early cases, published on April 14, no specific characteristics stand out – just over half were female, all were white and there was not a “discernible geographic pattern”.
Further reports from UKHSA labs are expected next week but, for now, firm answers elude scientists to two big questions: what is causing this spate of hepatitis, and how far might it spread?
Hepatitis – a broad term used to describe liver inflammation – can be caused by a range of issues, including a virus, toxins, fungi or even damage caused by drinking alcohol. In up to 20 per cent of cases, no cause is identified.
But the scale of the current outbreak, combined with a complete absence of the “usual suspects”, is baffling scientists. None of the patients tested positive for hepatitis A, B, C, D or E, nor other likely culprits – such as cytomegalovirus (CMV), which causes cold sores and chickenpox, and Epstein-Barr virus, which causes glandular fever.
Prof Deirdre Kelly, an expert in pediatric hepatology at Birmingham Women’s & Children’s Hospital, helped set up Britain’s liver transplant network some three decades ago. In early April, while on holiday in France, she got a call from the UKHSA that set her mind running. She didn’t have to look far to realize there was an issue.
“We do normally see, every year, some children with severe hepatitis for which we don’t know the cause, with a peak in spring suggesting it’s linked to a virus,” she said. “But this year is a big jump. In 2018, we saw six such cases between January and April in Birmingham. This year we’ve had 40.”
Currently, experts suspect an adenovirus is the culprit. So far, 77 per cent of cases in the UK tested positive for an active adenovirus infection, plus five of the nine cases in Alabama.
These infections are incredibly common – especially among children – but they usually cause cold symptoms, sometimes pneumonia. Only in rare cases in immunocompromised patients have they been known to cause hepatitis.
“That gives rise to the possibility that this might be an unusual or mutated adenovirus,” said Prof Kelly. “Although so far, it doesn’t look abnormal.”
Another, related theory is that the virus’s impact has been amplified by a lack of exposure to common adenoviruses during lockdowns.
But it’s not a slam dunk. In Denmark, where four cases have been confirmed, no children have tested positive, said Prof Anders Koch, infectious disease specialist at Denmark’s Statens Serum Institut.
“We haven’t seen the same signal with the adenovirus, but we have looked,” he told The Daily Telegraph. “So what you are seeing in England may be different from what you see in Denmark.”