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

Abstract

Students who had received a third dose of MMR vaccine had a lower risk of mumps than did those who had received two doses, after adjustment for the number of years since the second dose. Students who had received a second dose of MMR vaccine 13 years or more before the outbreak had an increased risk of mumps. These findings suggest that the campaign to administer a third dose of MMR vaccine improved mumps outbreak control and that waning immunity probably contributed to propagation of the outbreak. (Funded by the Centers for Disease Control and Prevention.).

Cost of Public Health Response and Outbreak Control With a Third Dose of Measles-Mumps-Rubella Vaccine During a University Mumps Outbreak—Iowa, 2015–2016

“…The third study was conducted during the outbreak at the University of Iowa where we performed the cost study. That study found that a third dose of MMR vaccine was associated with a lower incidence of mumps, with an incremental vaccine effectiveness of the third dose vs the second dose of 78% (95% confidence interval, 61%–88%) at 28 days postvaccination [13]. The evidence remains limited and insufficient to fully characterize the impact of a third dose of MMR vaccine on reducing the size and duration of an outbreak.…”

“…Compliance data are available from the university’s electronic database. Before the 2015 fall semester, 98% of students had documentation of ≥2 MMR vaccine doses [13]. In summer and fall of 2015, a large mumps outbreak was reported at the university.…”

“…Administration of a third dose of MMR vaccine was neither a standard public health response to outbreaks nor a routine recommendation. A 2017 study showed a significant reduction in mumps incidence among third-dose MMR vaccine recipients [13]. …”

“…An economic assessment of mumps outbreaks in universities, the primary setting where US mumps outbreaks occur, has not been performed. We assessed the costs of response activities during a 2015–2016 mumps outbreak in a university where the public health response included a university-wide third-dose MMR vaccination campaign [13, 17] to describe the economic burden of mumps outbreaks in university settings.…”

Mumps epidemic in North America proves unusually stubborn

“…A September study published in the New England Journal of Medicine found that a third dose of the measles, mumps, and rubella (MMR) vaccine sharply reduced infection risk when given to vaccinated students during an outbreak at the University of Iowa. 2 Most cases in the US and Canada-which has also seen mumps surge-have occurred in the 18-35 age group, among people too young to have had childhood mumps but old enough for immunity from their childhood MMR vaccination to have waned.…”