Health officials are warning of a possible outbreak of measles in Kent after 18 cases of the disease were reported in the Medway towns.
Dr Chandrakumar blames low MMR take-up for the outbreak
Three adult prisoners at Elmley Prison on the Isle of Sheppey have gone down with the virus, along with six children at Lordswood Primary School, Chatham.
The others are individual cases which have been reported to GPs.
Kent Health Protection Agency blamed the cases on low take-up of the MMR jab, which was below 82% in Medway.
Three of the 18 reported cases have been confirmed, with 15 more suspected. Two of the affected children are in hospital.
Letters to parents
The agency has written to GPs warning them of the outbreak and asked them to ensure that unvaccinated children and young people under 25 are offered MMR.
Letters have also been sent to Lordswood parents, while prisoners at Elmley will be offered the jab on Thursday.
"We have never had this number of cases of measles in Kent," said director of the agency Dr Mathi Chandrakumar.
"Because vaccine coverage is below what I would like to see, this may be the beginning of an outbreak of measles."
Doctors ideally want to see at least 90% take-up of MMR in young children but it has dropped because of health scares in recent years.
Dr Chandrakumar said studies had shown the combined measles, mumps and rubella vaccine was completely safe.