Could worrying outbreak of child hepatitis really be down to Covid?

Some experts insist it is. Others say they’re misguided. So who’s right?

LAST week, hundreds of experts in liver health gathered for the World Hepatitis Summit, and one topic dominated the agenda: the mysterious outbreak of hepatitis in children which has gradually spread across 34 countries – including the UK.

Speaking at the event, liver expert Dr Philippa Easterbrook said: ‘It is the first time so many severe cases have been seen in children. It is important we understand the cause and take these cases seriously.’

At its most extreme, hepatitis can cause the liver to stop working. So far, more than 240 cases have been reported in the UK, while 11 British children have needed a transplant.

What could be behind this is a subject that divides the scientific world. But the latest development comes from intriguing research by Israeli scientists which suggests the answer may lie with Covid-19.

Doctors analysed the medical history of five children who developed the condition – which is dangerous inflammation of the liver.

They noticed one common factor: all had caught Covid within the previous year. The liver inflammation, they suggested, may be an extreme side effect of the immune system response to the virus.

Influential doctors took to Twitter to share news of the findings, coining the phenomenon ‘long Covid liver’. British epidemiologist Dr Deepti Gurdasani, from Queen Mary University of London, tweeted her confidence in the findings, accusing some who dismissed them as ‘denying the damage Covid has had on children’. Yet numerous highly respected paediatric health experts and epidemiologists have angrily disputed the claims.

Professor Alasdair Munro, an expert in paediatric infectious diseases at University Hospital Southampton, said the study provides ‘almost no useful information’ and no evidence that these hepatitis cases are linked to Covid.

While Dr Jake Dunning, an infectious disease expert at the University of Oxford, said scientists branding the disease long Covid liver ‘really should know better’.

The prevailing theory is that a nasty strain of a common childhood infection called adenovirus is to blame – three-quarters of children admitted to British hospitals have tested positive for this variant.

MOST children will pick up the infection at some point but it usually causes just minor problems with the upper respiratory tract, leading to a cough, runny nose and, in rare cases, pneumonia.

But experts think a lack of exposure to adenoviruses during the Covid lockdowns has left children’s immune systems without natural protection to fight it off, leading to a severe reaction. Even so, the new claims may reignite worry among parents – so could they be right?

On the surface at least, the Israeli research appears convincing. The report, published in the Journal Of Pediatric Gastroenterology And Nutrition, tells of five patients: two aged three who needed liver transplants, and two eight-year-olds and a 13-year-old who were hospitalised but made a full recovery. All five were infected with Covid within the four months leading up to their hepatitis diagnosis.

The authors say their findings suggest a Covid infection caused the immune system to malfunction and begin attacking the liver. This is not unheard of with other viral infections, and in this case is known as post-viral hepatitis, a recognised condition in children.

Dr Gurdasani, a vocal supporter of the long Covid liver theory, says another piece of evidence is the fact that the UK and US have seen the largest number of hepatitis cases. Both had very high infection rates in children, unlike many other nations which enforced strict Covid-safety measures in schools.

‘The UK has been an outlier in how we tried to protect children from the virus,’ says Dr Gurdasani. ‘We didn’t enforce mask-wearing in the same way as other countries, and we haven’t done anything to ventilate schools. It’s possible we’re seeing the impact of those decisions.’

The study also casts doubt on the other probable cause: adenovirus wasn’t detected in any of the five patients. And it’s not the only study of its kind that’s reached that conclusion. At the end of April, doctors in Alabama published research noting the absence of the virus in nine children with severe hepatitis who required a transplant.

And many scientists have pointed out that adenovirus has never before been linked to hepatitis – in fact, there is not a single case of adenovirus triggering hepatitis reported in the medical literature. ‘The argument this is caused by an adenovirus gets weaker and weaker,’ says Dr Gurdasani. ‘It doesn’t cause hepatitis and multiple studies have failed to find it in the livers of these children. So where’s the evidence?’

But experts say there are multiple problems with the Israeli study. The biggest: it’s just five children.

Israel has recorded 12 child hepatitis cases, so the study includes fewer than half of these patients.

‘The researchers don’t explain why these patients were selected, or why the other hepatitis cases were not,’ says Prof Munro. ‘We don’t know if they only picked those that had Covid, so this doesn’t tell how likely it is a child who develops Covid will develop hepatitis.’

PROF Munro also points out that since Covid has been so prevalent, it is not necessarily surprising these children had Covid infections. ‘Covid infection is so common and the time lapse between these children getting the virus and then hepatitis is so varied, there isn’t any clear evidence that one is causing the other. That’s not to say Covid and hepatitis aren’t linked, but this study doesn’t provide any concrete proof they are.’

Prof Will Irving, a virologist at the University of Nottingham, agrees that it is too early to jump to conclusions. He says: ‘Five cases isn’t enough to prove anything, we need to look carefully at how many of the several hundred UK cases have had Covid and go from there.’

To add to the confusion, last week US health officials said that while the country had seen more than 270 cases of unexplained hepatitis in children this year, this is no more than it sees in a normal year. ‘There has always been a background level of these unexplained cases, even before Covid,’ says Prof Irving.

The one thing all experts agree on is that finding the cause remains an urgent task as it will help doctors know what treatment to give. In the UK, children hospitalised with hepatitis are treated for adenovirus – using the antiviral drug cidofovir. But other countries, such as Israel and Austria, are treating them with steroids, which can help regulate a malfunctioning immune system potentially impacted by Covid.

Dr Gurdasani warns: ‘If the adenovirus theory is wrong, we’ve been giving patients the wrong treatment for months. UK health officials need to focus on the Covid theory if they want to protect children.’