Over 500 people have been diagnosed with measles in and around Swansea, according to Public Health Wales (PHW).
The new data reveals that there have been 541 cases of measles in the area, as 100 new cases have been reported in the past week alone.
Health experts in the region are urging parents to make sure that their children have had the MMR vaccine. Measles can lead to serious complications for children, primarily deafness and brain damage. In some cases, children have also died from measles. Furthermore, even some babies have been offered the vaccine seven months earlier than recommended due to the epidemic. With uptake of the vaccine being at 89 per cent in the affected areas, the focus now is being shifted further afield.
Dr Marion Lyons, director of health protection for PHW, said: "Unfortunately some parents are continuing to put their children at unnecessary risk of catching this potentially serious disease. They need to get their children vaccinated without delay. The alarming numbers of cases of measles and continuing spread of the disease in Wales illustrates how vital it is for parents to get their children vaccinated."
The majority of the cases tend to be in Hywel Dda, Abertawe Bro Morgannwg and Powys. As more and more children come into contact with those already infected, they are increasing the risk of them suffering from permanent hearing loss in the future. Many of these children will then need to rely on hearing aids for the rest of their lives.
Doctors fear that the epidemic could reach the heights of the outbreak in Dublin in 1999, when over 1,200 children were affected and many became deaf.
An Abertawe Bro Morgannwg Health Board spokesperson said that no appointments were necessary for the jab and that parents should bring in their children as soon as possible.