Staff at hospitals in Swansea are the latest group to be targeted for vaccination against measles. Clinics will be set up at all health units to ensure that staff are protected from the disease.
Over 800 cases of measles have now been reported in the Swansea area however a further increase is expected as new figures are released later.
So far 77 people have needed hospital treatment since the outbreak began in November.
Health workers are considered to be at greater risk of contracting or incubating the disease, since they are at the forefront of all efforts to control it. Health chiefs are concerned that if they fall ill, it could have double the impact as they will need care themselves whilst also reducing the number of staff available to deal with the disease as well as other hospital demands.
It has also been announced that 10 schools in Swansea and Neath Port Talbot with over 1,700 pupils will be offered the MMR jab this week, with measures now also being taken in Pembrokeshire, Carmarthenshire and Ceredigion.
Meanwhile tests are to investigate whether Gareth Colfer-Williams, who was found dead at his home in Swansea last week, died from measles or other causes.