Scientists are investigating the cause of an increase in hepatitis in children in at least 12 countries, including Ireland.

One death and around 190 unexplained cases of severe hepatitis have been reported around the world in recent weeks, according to the European Centres for Disease Prevention and Control (ECDC).

The outbreak was first reported in the UK, where 111 cases have been registered in young children.

At least 12 other countries have also recorded cases, including Ireland, the US, Spain, Denmark and the Netherlands.

On The Pat Kenny Show, Dr Zania Stamataki, Associate Professor in Viral Immunology at the University of Birmingham said the cases remain very rare.

“In my teams, we study liver diseases and we also study viral infection so, when we heard about these cases we definitely raised an eyebrow – but they are not very common at all,” she said.

“It does sound worrying if we think that 111 cases were reported in the UK since the beginning of the year. That is slightly higher than the levels for paediatric liver disease that were reported before the pandemic.”

Hepatitis

Hepatitis is an inflammation of the liver. It can be caused through viral infections or through the heavy alcohol use, medications or toxins.

Dr Stamataki said none of the children have tested positive for the viruses that commonly cause the inflammation – Hepatitis A,B,C,D or E.

No link has been established to the COVID-19 vaccine and researchers have yet to identify anything the children were all exposed to.

“That does not mean that a virus might not be to blame,” she said. “Full microbiology investigations are taking place and they have discovered that some of the children tested positive for adenovirus - which is the virus that can cause the common cold - and a few children have tested positive for COVID as well.

“This is not surprising at all because these viruses are currently circulating.”

Lockdown

One theory that is being explored is whether children’s immune systems have been weakened by long periods of lockdown during the pandemic.

“This is one of the things that we hypothesise because, of course, we have been protected for a couple of years and we haven’t really given a chance for our immune systems to develop immunity to common cold viruses such as adenovirus,” said Dr Stamataki.

“Many of us who have been exposed to adenovirus recently or have caught the common cold recently might have noticed that it may have knocked them out more so than it would have pre-pandemic.”

She said "full investigations" have been ordered into the cause of the condition in each child – noting that the outcome will determine their treatment.

In all, 40 cases have been recorded in the European Union and European Economic Area in recent weeks.

Fewer than five cases have been detected in Ireland in recent weeks.