ACIP recommends third MMR dose during mumps outbreaks

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  • The Advisory Committee on Immunization Practices (ACIP) has released an updated guidance recommending a third measles, mumps, rubella (MMR) vaccine dose for persons (previously vaccinated with 2 doses) with increased mumps risk during an outbreak.
  • Although current recommendations for 2 doses suffice for the general population, waning immunity coupled with high-intensity exposure may be insufficient to prevent mumps; these individuals are now considered to be a public health priority for preventing severe disease/complications.

Why this matters

  • Clinicians are encouraged to follow public health guidance for identifying at-risk individuals/groups during mumps outbreaks.
  • Contraindications/precautions are the same as those for routine 1-2 doses.
  • During outbreaks, persons at increased risk who have not received 2 MMR doses or have unknown vaccination status should receive 1 dose.

Key points

  • In recent years, mumps outbreaks have occurred in populations in institutional settings with close contact or close-knit communities.
  • Even where 2-dose MMR coverage is high, it has been insufficient to prevent outbreaks in prolonged, close-contact environments; waning protection after the second dose contributes to higher risk in these settings.
  • Benefit of adding a third dose outweighs risk for adverse events (AEs), which have reportedly been low and nonserious.
  • AEs should be reported to the Vaccine Adverse Event Reporting System.