Conference Coverage

ACIP recommends third MMR dose, if outbreak risk



The Advisory Committee on Immunization Practices voted Oct. 25 to recommend a 3rd dose of measles, mumps, and rubella (MMR) vaccine for individuals at mumps risk from an outbreak.

The recommendation applies to individuals who already have been vaccinated with the usual two doses of MMR “who are identified by public health as at increased risk for mumps because of an outbreak,” according to draft text of the recommendation. This practice would “improve protection against mumps disease and related complications.”

Doctor holding digital tablet with mumps written on the screen. stockce/Thinkstock
Multiple mumps outbreaks have been reported since 2015, mostly in university settings, Mona Marin, MD, CDC, said in a presentation at a meeting of the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices.

Young adults are at highest risk, she said.

Key evidence supporting the ACIP’s recommendation includes one recent study suggesting a 3rd dose of MMR is effective for mumps outbreak control (N Engl J Med. 2017 Sep 7; doi: 10.1056/NEJMoa1703309).

In that study, Cristina V. Cardemil, MD, of the CDC, and her colleagues looked at college students who received a 3rd MMR dose during an outbreak of at the University of Iowa in Iowa City. Almost a quarter of students (4,783 of 20,496) enrolled in the 2015-2016 academic year received a 3rd dose. Compared with two doses of MMR, students receiving three total doses had a 78% lower risk of mumps at 28 days after vaccination, investigators reported.

“These findings suggest that the campaign to administer a 3rd dose of MMR vaccine improved mumps outbreak control and that waning immunity probably contributed to propagation of the outbreak,” Dr. Cardemil and her colleagues wrote.

The vote in favor of a 3rd dose was unanimous among 15 voting members of ACIP. The committee’s recommendations must be approved by the CDC director before they are considered official recommendations.

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