New York Mumps Outbreak Tests Third MMR Dose


ATLANTA — An intervention to administer a third dose of the MMR vaccine during a mumps outbreak appears to have slowed transmission of the virus, but more data are needed before such a strategy can be recommended, preliminary findings suggest.

For 2 months beginning in January 2010, public health officials offered a third dose of the measles-mumps-rubella (MMR) vaccine in three schools in Orange County, N.Y., where, despite a high level of two-dose coverage among students, viral transmission had continued for more than 2 months, said Dr. Ikechukwu Ogbuanu of the Centers for Disease Control and Prevention.

The Northeastern outbreak—the largest in the United States since 2006—began in June 2009 and was traced to a fully vaccinated 11-year-old Hasidic boy from Orange County, N.Y., who had recently returned from the United Kingdom. He subsequently spent time at summer camp and then traveled to Brooklyn.

From June 17, 2009 to May 7, 2010, a total of 3,341 outbreak-related mumps cases were reported from four sites in the New York and New Jersey area, predominantly among members of Jewish communities. Multiple factors might have fueled the outbreak in this community, including high population density and prolonged exposure, Dr. Ogbuanu said.

For their study, the researchers focused on records from the three Orange County schools where most of the cases occurred and conducted a survey of 6th-12th graders to assess risk factors related to mumps viral transmissions.

In those three schools, a third dose of MMR vaccine had been offered to eligible 6th-12th graders between Jan. 19 and Feb. 2, 2010; uptake occurred among 83% (1,863 of the 2,255) of those eligible.

“Preliminary data suggest a positive benefit,” Dr. Ogbuanu said. As of June 2010, of the 108 cases of mumps reported after the intervention, only four of the patients had received the third dose.

Dr. Ogbuanu, however, was adamant about not offering recommendations. The efficacy of a third MMR dose in controlling mumps outbreaks has not been previously reported and, he emphasized, researchers are still assessing the impact of this intervention.

The only adverse effects reported were pain, redness, and swelling at the injection site; there were no life-threatening adverse reactions.

Disclosures: Dr. Ogbuanu reported having no conflicts of interest.

'Preliminary data suggest a positive benefit,' but further testing will be needed.


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