Dr Marion Jones on Wales' worst measles outbreak for a decade
Health chiefs in Wales are dealing with a "massive" measles outbreak, with numbers already four times the highest figure recorded over the past 13 years.
Four nursery school children were treated in hospital as part of 127 cases across mid and west Wales, while there are another 39 cases in Conwy.
The National Public Health Service (NPHS) in Wales saw 39 cases last year. Its highest figure in 2003 was 44.
Officials appealed for parents to take up the MMR vaccine.
Dr Mac Walapu, consultant in communicable disease control for the NPHS, said: "For as long as there are children who do not receive their MMR vaccinations, there is the potential for outbreaks of measles to happen and we would remind anyone in Wales, and not just in the affected area."
Children from the Hapus Dyfa nursery in Burry Port have been vaccinated
A spokeswoman added: "We need to be up front with parents."
She added: "We try not to be too scary when we talk to people about this, but children die of measles and children are impaired by measles. "It puts children in hospital. The reality it is that this is happening now, in Wales. Measles is very contagious."
She said the outbreak was set to be the biggest in Wales since the MMR vaccine was introduced in 1988.
Four children aged under two, who went to the Hapus Dyrfa nursery in Burry Port, were admitted to hospital but are now home.
The nursery has been following the NPHS guidelines and remains open.
Thirty two children have since been vaccinated.
Last week, the NPHS said its research had shown the MMR uptake in one school in the Carmarthenshire area was as low as 14.8%.
The vaccine needs a 95% uptake to achieve the herd immunity needed to ensure the disease cannot take a hold in individuals who are not vaccinated.
Latest figures show that 86% of two-year-olds in Wales have been given the MMR vaccine, ranging in different areas from 78% to 92%.
This is short of the 95% target which has already been achieved in Scotland. The figure for England is around 85%.
Official advice is that children should receive their first dose of the vaccine at the age of one and the second before they start school, and anyone in Wales who is older than this and has not received the full two doses of the vaccine should come forward for immunisation.
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