The Health Service Executive has said any Irish teenagers who did not receive the MMR vaccine should get the jab now.

A public health campaign, highlighting the importance of childhood immunisation in preventing serious disease, is being launched in Ireland today to coincide with European Immunisation Week.

The campaign comes as authorities deal with a major outbreak of measles in South Wales.

Latest figures put the number of reported cases there at over 800.

Dr Brenda Corcoran of the HSE National Immunisation Office said it is vital that children are vaccinated and that a catch-up campaign is also under way in secondary schools.

"Measles is highly infectious, a child with measles can infect almost all the children they come in contact with if it is not protected," she said. 

"It can lead to serious pneumonias; it can lead to convulsions and unfortunately in some circumstances it can lead to death. When we had a very large outbreak in 2000, we had 1,600 cases and unfortunately three children died from measles."