UK health officials say they are still no clearer on the cause of a rise in liver inflammation, or hepatitis, in children.
A common adenovirus is thought to play a role, but other possibilities are still being investigated.
In the UK, 163 cases have now been identified, and 11 children have received liver transplants.
Cases have been detected in 20 countries worldwide, with nearly 300 children affected, and one death.
"It's important that parents know the likelihood of their child developing hepatitis is extremely low," said Dr Meera Chand, from the UK Health Security Agenc