The NHS has sent letters to parents of six to 11-year-olds in England, urging them to make an appointment with their GP if their child has not had both vaccine doses.
London, the epicentre of the outbreak, has logged 59 suspected cases of the highly contagious virus since November 27. Birmingham has reported 48 infections.
As few as half of children have had both measles, mumps and rubella (MMR) jabs in parts of London. Similarly low levels are also seen in Liverpool, Manchester and Birmingham.
Ellie Roscoe, from Harborne in Birmingham, never had her second vaccine in 1998 before starting school after bogus studies linked the vaccine to autism.
More than 300 cases have been identified since October, leading to 50 children being admitted to Birmingham Children s Hospital for treatment in the last month.