Parents or carers of children who are five or under in the Barry area are being urged to take up the offer of Hepatitis A vaccines for their child.
An outbreak in the Vale of Glamorgan town has seen 11 confirmed cases since December 2025.
Public Health Wales said Hepatitis A is spreading in the community, but that no single source has been identified and that vaccinating children will help protect them, their families and the wider community.
Hepatitis A can be present in young children without any obvious symptoms.
The free vaccines will be offered at Barry Hospital between Tuesday, 18 August and Saturday, 22 August 2026.
Dr Chris Williams, a consultant epidemiologist at Public Health Wales said the vaccine is necessary to try to control the outbreak
“The easiest place for it to spread from is from with young children under the age of six and so if we can vaccinate that age group that will prevent the transmission from those children and stop the spread,” he said.
Those eligible will receive a letter or text from Cardiff and Vale University Health Board, inviting them to take up the offer of a vaccination.
The vaccine is being offered to children five or under who live in Barry or attend a childcare setting in the town.