Mumps Outbreak — New York, New Jersey, Quebec, 2009

P High, MPH; EF Handschur, MPH; OS Eze, MD; B Montana, MD; C Robertson, MD; C Tan, MD; JB Rosen, MD; KP Cummings, MPH; MK Doll, MPH; JR Zucker, MD; CM Zimmerman, MD; T Dolinsky; S Goodell, MPH; C Schulte; D Blog, MD; MA Leblanc; YA Li, MD; A Barskey MPH; G Wallace, MD; K Gallagher, DSc; G Armstrong, MD; L Lowe, MS; R McNall, PhD; J Rota, MPH; P Rota, PhD; C Hickman, PhD; WJ Bellini, PhD; A Apostolou, PhD

Disclosures

Morbidity and Mortality Weekly Report. 2009;58(45):1270-1274. 

In This Article

Editorial Note

Before routine mumps vaccination was initiated, most persons acquired infection during childhood. In 1967, a live, attenuated mumps virus vaccine was licensed in the United States, and by 2005 high coverage with 2 doses among children had reduced the incidence of mumps by 99%.[2] In 2006, a resurgence occurred in the United States, with the highest attack rate among persons aged 18–24 years; 57% of patients had previously received 2 doses of vaccine.[2] In 2007 and 2008, incidence declined to 800 and 454 cases, and outbreaks involved fewer than 20 cases.

The ongoing mumps outbreak is the largest since 2006 and primarily has affected a tradition-observant religious community. Mumps outbreaks perpetuated by community transmission outside of congregate settings (e.g., camps, schools, and colleges) are unusual in highly-vaccinated populations.[2] In this outbreak, the limited transmission of mumps into the general population might be attributable to generally high vaccination levels and little interaction between members of the affected religious community and persons in surrounding communities. Vaccination rates in the religious community in this outbreak have not been measured, but according to the 2008 National Immunization Survey, overall age-appropriate mumps vaccination rates for children in New York City, New York state, and New Jersey were high: ≥90% for receipt of 1 dose among children aged 19–35 months and ≥90% for receipt of 2 doses among adolescents aged 13–17 years. However, mumps incidence commonly peaks in the winter,[2] and vaccine-preventable diseases have spread from religious communities to the general population during the peak transmission season.[7]

Of those patients in this outbreak whose vaccination status was known, 72% had received 2 doses of mumps-containing vaccine, compared with 57% in the 2006 outbreak. Mumps vaccine effectiveness has been estimated at 73%–91% for 1 dose and 76%–95% for 2 doses.[8,9] Studies during the 2006 U.S. mumps resurgence suggested that outbreaks could occur among highly-vaccinated populations such as college students, where frequent close contact occurs and where > 10 years have passed since most of the population received a second dose.[9] However, even in such settings, attack rates were < 8% in 2006 for those with 2 doses, suggesting that the vaccine was highly effective in preventing disease for the vast majority of those exposed.[9] In the current outbreak, the attack rate at the summer camp was approximately 6%.

Because 43% of the world's nations have no mumps vaccination program,[10] and certain nations with mumps vaccination programs, such as the United Kingdom, have experienced large-scale outbreaks, the risk for mumps exposure is increased with foreign travel. When importations occur, congregate settings in the United States, such as colleges and schools, have been foci of indigenous mumps transmission.[2]

When possible, persons with suspected mumps should be isolated for 5 days after onset of parotitis and, if they visit a health-care setting, droplet precautions should be initiated immediately. Clinical specimens (both serum and buccal swabs) should be collected from persons with suspected mumps as soon as possible after symptom onset. Adults and children should receive age-appropriate vaccination. University students, health-care personnel, and persons with potential mumps outbreak exposure should have documentation of 2 doses of mumps vaccine or other proof of immunity to mumps. Although vaccination is not considered effective postexposure prophylaxis for mumps, nonimmune contacts should be vaccinated with measles, mumps, rubella (MMR) vaccine to prevent risk from subsequent exposures. Any suspected mumps case should be reported to the health department in the area where the patient resides. Additional information regarding mumps vaccination is available at http://www.cdc.gov/vaccines/vpd-vac/mumps/default.htm#recs.

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