By Dave Koch | Guest Column
When Johnson County experienced a large mumps outbreak associated with the University of Iowa from July 2015-May 2016, a partnership between several organizations helped control it.
The University of Iowa requires students to have two doses of the MMR vaccine. Due to this requirement, prior to the outbreak 98.1 percent of students had received at least two doses of the MMR vaccine.
The effectiveness of the mumps vaccine is estimated to be about 88 percent when a person receives both recommended doses and about 78 percent if they receive a single dose. Despite the very high percentage of students who had received two MMR vaccinations, the outbreak continued.
That November, in an effort to control the outbreak, the University of Iowa and partners hosted eight mass vaccination clinics that gave a third MMR vaccine to more than 4,700 students.
The first confirmed case of mumps in Johnson County occurred during the week of June 21-27, 2015, with four confirmed cases during the week of July 12-18, 2015. New cases remained steady at around three new cases occurring every two to three weeks through August and September. Confirmed cases began to increase in the University of Iowa student population in late September with a peak of 23 confirmed cases the week of Sept. 27-Oct. 3.
In consultation with the Centers for Disease Control and Prevention (CDC) and the Iowa Department of Public Health (IDPH), a third dose for all college students under the age of 25 was recommended. There was discussion regarding the effectiveness of a third dose due to conflicting research studies.
All partners agreed that a third MMR should be offered and two mass vaccination clinics were planned for Nov. 10-11, 2015. Partners on the conference calls discussed the best timeframe for clinics. With the Thanksgiving break two weeks away, it was important to get the vaccine to students as soon as possible for maximum effectiveness.
Getting the vaccine to the students prior to break would allow protection to develop before the students returned to the UI and had additional mumps exposure. This was also done to help limit the spread of mumps from the university to the students’ home communities.
Communications were sent to Johnson, Linn, and Cedar County Medical Reserve Corps through coalition partners, notifying them of the clinics and asking for capacity for medical and non-medical volunteers for the November clinics.
This September, an article – “Effectiveness of a Third Dose of MMR Vaccine for Mumps Outbreak Control” – written in partnership between the CDC, the University of Iowa, Johnson County Public Health and IDPH, was published in the New England Journal of Medicine.
Through statistical analysis, this article shows that students who received the third MMR dose were significantly less likely to contract mumps than those who did not receive the additional dose. The conclusion was that “these findings suggest that the campaign to administer a third dose of MMwww.cdc.gov/mumps/index.htmlR vaccine improved mumps outbreak control and that waning immunity probably contributed to propagation of the outbreak.”
Over the past several years, outbreaks of mumps have occurred at college campuses around the country. Our hope is that these findings will lead to official recommendations for a third dose of MMR vaccine in outbreak settings. This would give public health and student health departments across the country another tool to help put an early end to mumps outbreaks.
The full article, and a brief two-minute video summarizing the findings, can be found at http://bit.ly/2wpAmvW. For more information about mumps in general, visit the CDC website at www.cdc.gov/mumps/index.html.
Dave Koch is Johnson County Public Health Director.
