1424. Increasing Incidence of Measles in the United States, 2001-2015
Session: Poster Abstract Session: Public Health
Friday, October 28, 2016
Room: Poster Hall

Background: Measles is a highly contagious, vaccine-preventable disease that can lead to serious complications and death. High measles-mumps-rubella (MMR) vaccine coverage in the United States led to declaration of measles elimination (interruption of year-round endemic transmission) in 2000; however, importations from endemic countries continue to occur. Recent outbreaks have captured media attention, prompting discussions on vaccine hesitancy, concerns for measles reemergence, and possibility of vaccine failure. We describe the incidence of measles among US residents and examine temporal trends post-elimination.

Methods: We assessed reports of confirmed measles cases from state health departments to the Centers for Disease Control and Prevention from January 2001 through December 2015. Overall and age-specific incidence rates (IR) were calculated by dividing the annual number of measles cases by corresponding US Census Bureau’s Bridged Race population estimates.

Results: From 2001-2015, 1788 cases of measles were reported among US residents. Most case-patients were unvaccinated (69%) or had unknown vaccination status (18%). Overall measles IR was 0.39 per 1,000,000 persons. Incidence was higher in infants (6-11 mo; 5.50 per 1,000,000) and toddlers (12-15 mo; 5.43 per 1,000,000). Although measles IR remained at <1 per 1,000,000 persons every year except in 2014 (1.98 per 1,000,000), a rate increase was noted in recent years. Among 532 cases directly imported into the country, 62% were US residents returning from travel abroad, with the proportion of imported case-patients who were US residents increasing over time.

Conclusion: The incidence of measles remains low in the US and is consistent with the absence of endemic measles transmission. Although there was yearly variability, the higher incidence in recent post-elimination years and the increase in the number of US travelers as a source of importations, emphasizes the importance of 2 doses of MMR vaccine among international travelers. Health-care providers should maintain heightened awareness in returning travelers who present with rash illnesses.  Finally, US support of measles control in other nations will further limit transmission in the US. 

Nakia Clemmons, MPH, Ncird, Centers for Disease Control and Prevention, Atlanta, GA, Paul Gastanaduy, MD, MPH, Epidemiology Branch, Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA and Gregory S. Wallace, MD, MPH, MS, Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA


N. Clemmons, None

P. Gastanaduy, None

G. S. Wallace, None

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