GPs in Merseyside have launched an urgent MMR vaccination drive after a measles outbreak.
The Health Protection Agency said a team of specialists were investigating 48 laboratory confirmed cases, 37 probable cases and 108 possible cases in the region.
The majority of the cases are in children under the age of five who were not vaccinated at the optimum age of 13 months, and babies and toddlers who are too young to be vaccinated.
A HPA statement said that a search of GP records revealed over 7,000 children under the age of five in Halton, St Helens, Knowsley, Liverpool and Sefton were not immunised at the optimum age of 13 months and therefore are vulnerable to infection.
The statement said: ‘PCTs are writing to the parents of these unprotected children, advising them to arrange vaccination through their family doctors.'
Dr. Roberto Vivancos, a consultant with the HPA's Cheshire and Merseyside Health Protection Unit, said: ‘When unvaccinated older children pick up an infection they can pass it on to vulnerable infants who are too young to be vaccinated. That would appear to be what's happening in this outbreak.'
