654. Mumps, 2016: A National Overview
Session: Poster Abstract Session: Outbreaks and Public Health Across the Globe
Thursday, October 5, 2017
Room: Poster Hall CD
Background: Mumps is an acute viral illness that classically presents with parotitis. Infected persons who are asymptomatic or have non-specific respiratory symptoms can still transmit disease. Recently, mumps cases and outbreaks (OB) among young adults (18-22 yrs) in the US have been increasing. In 2016, university and close-knit community OB accounted for the highest incidence rates (IR) since 2006 (FIGURE 1).

Methods: The Centers for Disease Control and Prevention (CDC) assessed reports of confirmed and probable mumps cases transmitted through passive surveillance by 52 state/local health departments (jurisdictions). Nine jurisdictions submitted enhanced OB data including symptoms and complications directly to CDC. We calculated overall and age-specific IR (per 1,000,000 persons, 95% CI) by dividing the annual number of mumps cases by U.S. Census Bureau’s population estimates. SAS (v9.4) was used for analysis.

Results: From January – December 31st, 2016, 5724 mumps cases from 48 jurisdictions were reported (overall IR: 18). Of 79% with vaccination status, 88% had ≥1 dose and 60% had ≥2 doses of measles mumps rubella (MMR) vaccine. Median age was 20 years (range: <1 – 88 yrs). Incidence rates significantly increased for all age groups from 2011 to 2016 (1.2 (CI: 1.2-1.4) to 18 (17-18), P<.0001). IR in young adults increased from 4.1 (CI: 3.3-5.0) to 70 (CI: 66-73), P<.0001. (FIGURE 2). Twenty-nine jurisdictions reported mumps OB (defined as ≥3 cases linked by time/space); OB accounted for ~81% of all cases. Two states, Arkansas and Iowa, contributed 53% of all cases. Among jurisdictions with enhanced OB data, 20 OB (median 12 cases, range: 3-685) with a total of 1379 outbreak cases were reported. Parotitis was reported in 99% of cases. Complications were low: orchitis was reported in 7% of males and oophoritis in 2% of females; ≤1% reported hearing loss, mastitis, encephalitis or pancreatitis. Average report time from symptom onset to health department was 6 days. Ten OB had population vaccination coverage ≥85%.

Conclusion: OB contributed to a significant increase in mumps incidence in 2016. Although most cases occurred in young adults vaccinated with 2 doses during childhood thus suggesting waning immunity, complications remain rare.

Nakia Clemmons, MPH1, Adria Lee, MSPH2, Susan B. Redd, BS1, Janell Routh, MD, MHS1 and Manisha Patel, MD, MS1, (1)Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, (2)Ihrc, Inc, Contracting Agency to the Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA

Disclosures:

N. Clemmons, None

A. Lee, None

S. B. Redd, None

J. Routh, None

M. Patel, None

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