A hepatitis outbreak could be linked to the fact that people have kept their distance from each other due to the pandemic.

That's according to Professor Sam McConkey - head of the Department of International Health and Tropical Medicine at the Royal College of Surgeons in Ireland.

He was speaking as seven more possible cases of unexplained hepatitis in young children are under investigation by health authorities here.

The Health Protection Surveillance Centre (HPSC) says no single virus has been identified in the cases.

Investigations are ongoing to identify the cause.

One child has died and another received a liver transplant associated with this disease.

The World Health Organisation (WHO) says the overall number has risen to 429 in 22 countries.

Prof McConkey told Pat Kenny he believes social distancing, as a result of the pandemic, may have played a part.

"It could be a link to the social distancing we've all had.

"We've all been sort of not physically interacting with as many people for the last couple of years.

"So little children haven't been getting their usual childhood exanthems - their fevers, and snotty noses that children normally get in the first couple of years of life.

"Those normal things have been deferred potentially for a year or two because of the social distancing that we've all suffered from."

Prof McConkey says there are likely one of three reasons for this outbreak.

"It'll probably be one these three: first there's a toxin that could be in the environment from chemicals that we're exposed to - or in our food chains, which are very international as we all know.

"The second interesting possibility is that it could be a new virus - and we're all, of course, familiar with SARS-CoV-2 that didn't exist two or three years ago.

"So this could be a new virus: people are looking for 'Hepatitis H' virus - we have A, B, C, D, E - and there is a 'G'.

"So a new type of virus that could cause it. So far, nothing's come up on that".

And he says the third possibility could be "a new manifestation, a new presentation, of an old virus."