Effectiveness of a Third Dose of MMR Vaccine for Mumps Outbreak Control

The New England Journal of Medicine

https://www.nejm.org/doi/full/10.1056/NEJMoa1703309

During a recent outbreak of mumps in a group of vaccinated students at the University of Iowa, health officials implemented a widespread MMR vaccine campaign.  Students usually receive a total of 2 doses of MMR vaccine prior to entering college, based on college entry requirements.  This additional dose was implemented in order to try to control the mumps outbreak and see if immunity was lessening over time for students who had been fully vaccinated.  The results of the study showed that students who received a third dose of MMR vaccine had a lower risk of mumps than did those who had received two doses.  Public health continues to promote herd immunity as the best way to prevent outbreaks from occurring in a community and to protect those who are medically at risk (compromised immune systems, etc).  The findings of this study suggest new methods for protecting our community during an outbreak period.