The Advisory Committee on Immunisation Practices (ACIP) recently recommended that a third dose of MMR vaccine be given in the event of an outbreak of mumps for individuals previously vaccinated with 2 doses.

This recommendation was based on a study of a mumps outbreak at a university with some 20 000 previously immunised students. 5000 of these students received a third dose of MMR after the outbreak. These students experienced a significantly lower incidence of mumps seven days after vaccination.

A third dose of MMR vaccine can be considered during an outbreak of mumps for patients who have completed their two dose course of MMR more than two years previously.

See the original Pubmed abstract here.