title: A Comparison of Postelimination Measles Epidemiology in the United States, 2009-2014 Versus 2001-2008.
abstract: BACKGROUND
  Measles, a vaccine-preventable disease that can cause severe complications, was declared eliminated from the United States in 2000. The last published summary of US measles epidemiology was during 2001-2008. We summarized US measles epidemiology during 2009-2014.
  
  
  METHODS
  We compared demographic, vaccination, and virologic data on confirmed measles cases reported to the Centers for Disease Control and Prevention during January 1, 2009-December 31, 2014 and January 1, 2001-December 31, 2008.
  
  
  RESULTS
  During 2009-2014, 1264 confirmed measles cases were reported in the United States, including 275 importations from 58 countries and 66 outbreaks. The annual median number of cases and outbreaks during this period was 130 (range, 55-667 cases) and 10 (range, 4-23 outbreaks), respectively, compared with an annual median of 56 cases (P = .08) and 4 outbreaks during 2001-2008 (P = .04). Among US-resident case-patients during 2009-2014, children aged 12-15 months had the highest measles incidence (65 cases; 8.3 cases/million person-years), and infants aged 6-11 months had the second highest incidence (86 cases; 7.3 cases/million person-years). During 2009-2014, 865 (74%) of 1173 US-resident case-patients were unvaccinated and 188 (16%) had unknown vaccination status; of 917 vaccine-eligible US-resident case-patients, 600 (65%) were reported as having philosophical or religious objections to vaccination.
  
  
  CONCLUSIONS
  Although the United States has maintained measles elimination since 2000, measles outbreaks continue to occur globally, resulting in imported cases and potential spread. The annual median number of cases and outbreaks more than doubled during 2009-2014 compared with the earlier postelimination years. To maintain elimination, it will be necessary to maintain high 2-dose vaccination coverage, continue case-based surveillance, and monitor the patterns and rates of vaccine exemption.
authors.affiliation: Epidemiology Branch.
authors.forename: Amy Parker
authors.initials: AP
authors.lastname: Fiebelkorn
authors.affiliation: Epidemiology Branch.
authors.forename: Susan B
authors.initials: SB
authors.lastname: Redd
authors.affiliation: Epidemiology Branch.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Gastañaduy
authors.affiliation: Epidemiology Branch.
authors.forename: Nakia
authors.initials: N
authors.lastname: Clemmons
authors.affiliation: Measles, Mumps, Rubella and Herpesviruses Laboratory Branch, Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Rota
authors.affiliation: Measles, Mumps, Rubella and Herpesviruses Laboratory Branch, Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Rota
authors.affiliation: Measles, Mumps, Rubella and Herpesviruses Laboratory Branch, Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: William J
authors.initials: WJ
authors.lastname: Bellini
authors.affiliation: Epidemiology Branch.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Wallace
mesh_terms: D000367:Age Factors; D003430:Cross-Sectional Studies; D060740:Disease Eradication; D004196:Disease Outbreaks / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D017589:Immunization Programs; D007115:Immunization Schedule; D015994:Incidence; D007223:Infant; D008297:Male; D008457:Measles / Q000453:epidemiology* / Q000517:prevention & control*; D008458:Measles Vaccine / Q000008:administration & dosage; D011159:Population Surveillance; D014481:United States; D000073887:Vaccination Coverage / Q000706:statistics & numerical data
chemical_list: D008458:Measles Vaccine
keywords: epidemiology; measles; measles elimination; measles mumps rubella (MMR) vaccine