1425. Mumps outbreak characterization before and after a 3rd dose MMR vaccination campaign in a large university, Iowa, July 2015—April 2016
Session: Poster Abstract Session: Public Health
Friday, October 28, 2016
Room: Poster Hall
  • IDWeek poster Iowa Mumps.pdf (357.3 kB)
  • Background:

    Between July 15 and November 1, 2015, 114 cases of mumps were reported in a large Iowa university (~22,000 undergraduates) with a mandatory 2-dose measles, mumps, and rubella (MMR) vaccination policy. As a response to this outbreak, 3rd doses of MMR vaccine were offered to students <25 years old from November 10-19; 4,658 doses were administered, yet cases continued to occur.  We aim to characterize this mumps outbreak before and after the vaccination campaign.


      Case demographics, clinical symptoms and complications were determined by phone interviews and medical chart abstractions. CSTE case definitions were used. Vaccination status was verified with university and state immunization records. The post-intervention period began on December 10, 2015 (one incubation period after the final 3rd dose clinic) and ended on April 25, 2016. Cases among persons <25 vs. 25 years old were compared pre- and post-campaign using Fisher’s exact test.


    Of 277 confirmed and probable cases reported between July 15, 2015 and April 25, 2016 (Figure), 192 (69%) were confirmed by RT-PCR, median age was 21 (IQR 20-22) years, and 91% were undergraduates.  Of 205 students providing housing information, 113 (55%) lived in apartments, 50 (24%) lived in houses, 30 (15%) lived in dorms, and 12 (6%) lived in fraternity/sorority houses.  Prior to illness, 240 (87%) cases had 2 MMR doses, 31 (11%) had 3 doses, 3 (1%) had 1 dose, 2 (1%) had 0 doses; 1 had unknown vaccination history.  95% of cases had parotitis for ≥ 2 days, and median illness duration was 8 (IQR 6-10) days. Complications included meningitis (n=1), hearing loss (n=3), orchitis (n=14) and mastitis (n=2).

    Fewer cases occurred in the 5 months post-intervention (n=53, 19%) than the 5 months pre-intervention (n=224, 81%).  The proportion of cases <25 years old was lower post-intervention (91%) than pre-intervention (98%, p=0.01).


                   Despite high 2-dose MMR vaccine coverage, a large mumps outbreak occurred at an Iowa university. While fewer cases occurred overall and in the target population after a 3rd dose MMR campaign, further studies are needed to determine if this decline is due to the 3rd dose vaccination campaign.

    Machine generated alternative text:
Number of Cases
Illness Onset Date
Mumps cases in students at a large university, Iowa
July 13,2015 -April 25, 2016
Third MMR
Fall Semester
Semester Start
Spring Semester



    Minesh Shah, MD, MPH1, Cristina Cardemil, MD1, Andrew Weigel, CSW2, Jacob Riley, MSPH2, Lisa James, RN, MSN3, James Todd Patterson, BS3, Rebekah Stewart Schicker, MSN, MPH, NP-C1, Nakia Clemmons, MPH1, Nick Kalas, MPH4, Patricia Quinlisk, MD, MPH4 and Iowa Mumps Outbreak Response Team, (1)Centers for Disease Control and Prevention, Atlanta, GA, (2)Johnson County Public Health Department, Iowa City, IA, (3)The University of Iowa Student Health & Wellness, Iowa City, IA, (4)Iowa Department of Public Health, Des Moines, IA


    M. Shah, None

    C. Cardemil, None

    A. Weigel, None

    J. Riley, None

    L. James, None

    J. T. Patterson, None

    R. S. Schicker, None

    N. Clemmons, None

    N. Kalas, None

    P. Quinlisk, None

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