Health officials are working to establish the cause of a mystery form of hepatitis which has infected 16 young children in Northern Ireland.
More than 160 children across the UK have contracted the illness, referred to as non A-E hepatitis or sudden onset hepatitis, and 11 have required a liver transplant.
Cases have been detected in 20 countries worldwide and most cases have affected children under the age of five.
Northern Ireland’s chief medical officer Michael McBride urged parents to be aware and vigilant of the condition.
“On non A-E hepatitis in children, we have now 16 confirmed cases in children in Northern Ireland, some of whom have required specialist treatment in other parts of the United Kingdom, including one who has required a liver transplant," he said.
“We are very grateful for the joint work which has gone on across the United Kingdom, both in terms of the public health response and also working with clinical teams to ensure these children get the best possible treatment and care.
Mr McBride said the important thing at this time was to "maintain a high level of vigilance and awareness of this condition."
“There is ongoing investigation to determine the cause.
“It is obviously concerning when we are dealing with any new presentation, particularly when we are not absolutely clear at this point in time what is causing it," he added.
Dr Gillian Armstrong, from the Public Health Agency, said a range of factors were being examined to determine the cause of the condition.
“We can confirm that there are now 16 cases of sudden onset hepatitis in young children in Northern Ireland which have not been linked to any of the pre-existing causes of hepatitis in children such as hepatitis A-E or any other clear cause.
“We are continuing to work with our counterparts in other jurisdictions and investigations are being led by the UK Health Security Agency into the causes of these."
Dr Armstrong said work was ongoing to assess a wide range of possible factors.
“One of the possible factors that is emerging is a link to adenovirus infection. This is a relatively common childhood infection that we have seen and there is currently a case control study under way to determine if that is indeed behind this rise of hepatitis in young children.
“However, there are a range of other possible causes which are currently being investigated, including a number of other infections as well as looking into toxins and environmental exposures.”
“We can confidently say that there is no link to Covid-19 vaccine as the vast majority of these children were too young to have been offered the vaccine," she added.
“Hand hygiene and respiratory hygiene are the most important methods of preventing and controlling the spread of infections being investigated so we would ask parents to encourage children to wash their hands regularly.
“If you have a child who is showing signs of jaundice or you think their skin or the whites of their eyes have a yellow tinge, please do seek urgent medical attention.
“The risk to the overall population is low, it is relatively rare and the vast majority of children have recovered completely without any long-term affects. However, a very small number have had significant health complications and required liver transplant.”