MEASLES is out of control in Swansea and putting every baby in the area at risk.
Health chiefs say the situation is deteriorating week by week, with numbers doubling in the last three weeks and 51 people hospitalised — many of them infants.
And with 8,000 children in the Abertawe Bro Morgannwg University Health Board area not protected by the MMR jab, huge efforts are being made to reduce the figure.
The school health nursing service has run MMR sessions for susceptible children but that is being halted as, with 110 schools having one or more cases of measles, it cannot be contained.
Abertawe Bro Morgannwg University Health Board public health director Sara Hayes said 432 cases had been reported as of Monday this week — up from just over 20 on March 4.
"It is out of control and increasing week by week. We have more than 400 cases, mostly from Swansea but some from Neath Port Talbot and a few from Bridgend," she said.
"We have had more than 50 people hospitalised, many of them babies."
Children need two MMR jabs, one at just over the age of one and one shortly after they turn three. After the first they are 90 per cent immune, with the second jab providing 99 per cent immunity.
To protect babies aged one and under there needs to be what is known as herd immunity, where there is sufficient protection among the wider population.
To achieve herd immunity, there needs to be 95 per cent take-up of MMR, while the ABMU area has managed to achieve only a 75 per cent take-up.
As well as putting information on the internet, ABMU is asking GPs to check their records and letters will be sent to the parents or guardian of every child who is not had one or both jabs.
Health visitors are making contact with susceptible families. Midwives are also advising pregnant mums to have any other children in the household immunised.
Dr Hayes said: "It is a horrible disease. It can cause long-term deafness and blindness, encephalitis, and you can be left with learning disabilities.
"It can cause pneumonia, and children end up on ventilators. The big worry is that it can cause death."
Dr Hayes said there was an outbreak in Ireland a few years back, with 1,500 cases and three deaths.
"Our number is getting close to that level," she added.
"The one thing is that it seems to be affecting school-age children. Because they are slightly older maybe that has protected us from an adverse outcome. But it could happen any time."