Mumps Outbreaks Highlight Need for Immunization Documentation at Universities

Despite the high number of individuals who are vaccinated against the mumps, outbreaks are common occurrences in crowded environments. Since 2011, there have been multiple mumps outbreaks reported each year in various university communities, across the United States.

In 2016, 4 mumps outbreaks were confirmed at 4 universities across the state of Indiana between February and April, the Centers for Disease Control and Prevention (CDC) reports in a recent Morbidity and Mortality Weekly Report. Investigators found that documentation of receipt of 2 doses of the measles, mumps, and rubella (MMR) vaccine was not available, and, as such, implementing policies necessary for preventing spread of the disease proved difficult. To better manage outbreaks such as these in the future, immunization documentation requirements are needed in universities. Furthermore, those deemed to be at increased risk of infection should be administered a third dose of vaccine to improve protection against the disease.

Across the 4 outbreaks, there were a total of 281 confirmed and probable cases of the mumps reported amongst students and members of the surrounding communities who were not affiliated with the universities.

The outbreaks were a particular cause for concern due to the fact that only 216 (76.9%) of the individuals had documentation of presumptive evidence of immunity. The CDC defines presumptive evidence of immunity as one of the following: having received 1 dose of MMR (measles, mumps, rubella) vaccine at 1 year of age; 2 doses of MMR vaccine for school-aged children and adults at high risk for exposure and transmission of the mumps, including college students, health care personnel, and international travelers; blood tests that demonstrate immunity to the mumps; or laboratory confirmation of previous infection with the mumps.

Specifically, the CDC reports that receipt of 2 doses was documented for 152 (84.9%) of 179 university-affiliated cases and 53 (52%) of 102 cases in the surrounding community. Additionally, 12 cases (4.3%) had documentation of >3 doses of the MMR vaccine that had been administered more than 4 weeks before the onset of symptoms.

The CDC reports that isolation through 5 days post-parotid swelling onset was recommended for all individuals who had fallen ill; exclusion from classes, work, or public gatherings were recommended for those without presumptive evidence of immunity. However, because this information was not readily available in all universities, only 1 university was able to successfully implement both isolation and exclusion policies.

In response to the high number of individuals who were up-to-date on their MMR vaccinations but fell ill with the mumps, the Advisory Committee on Immunization Practices published new recommendations in January of 2018 which call for a third dose of MMR vaccine in individuals who are at an increased risk of infection during an outbreak.

Other efforts that were in place to prevent disease spread during the 2016 outbreaks in Indiana included holding 7 vaccination clinics across 3 of the universities. A total of 5273 doses of MMR vaccine were administered via the clinics. Health officials suggest that the majority of doses administered at the clinics were likely an individual’s third dose, based on the high 2-dose MMR coverage at each university.

According to the investigators, on-campus vaccination clinics that provide doses of the MMR vaccine could be beneficial to getting a larger amount of individuals vaccinated in a small time frame with little to no cost to students and staff. The clinics also provide an opportunity for health officials to educate individuals in an outbreak setting about signs and symptoms as well as ways to avoid infection.

The outbreaks highlight a need for standardized immunization documentation across universities, according to the CDC. Prior to these outbreaks, only 2 of the 4 universities required documentation of dose and the date of administration; furthermore, only 1 of those universities required provider verification of the student provided records. According to the authors, the remaining 2 universities’ lack of records caused substantial delays in identifying at-risk individuals.

Following the outbreaks, in fall of 2017, the remaining 2 universities instituted policies that require all students to submit immunization records that contain the date the vaccine was administered and verification by a provider.

Health officials indicate that now, should an outbreak pop up at 1 of the universities, it would be easier to pinpoint the students who do not have presumptive evidence of immunity based on a lack of documentation.

If outbreak management issues continue to arise in populations with high 2-dose coverage, despite the recommendation for use of a third dose of MMR vaccine during an outbreak, it will be necessary to reevaluate current recommended exclusion measures.