title: Measles elimination in the Americas: a comparison between countries with a one-dose and two-dose routine vaccination schedule.
abstract: BACKGROUND
  The Region of the Americas eliminated measles in 2002 through high first-dose routine measles vaccine coverage and vaccination campaigns every 4-6 years; a second routine dose at school entry was added in some countries. The impact of this second routine dose on measles elimination was evaluated.
  
  
  METHODS
  Data on socioeconomic factors, demographic characteristics, vaccination coverage, and the estimated proportion of children (<15 years of age) susceptible to measles were compiled. Countries were grouped using propensity score methods, and Kaplan-Meier curves were used to compare time to measles elimination between countries with a 1-dose schedule and those with a 2-dose schedule.
  
  
  RESULTS
  One-dose (n = 14) and 2-dose (n = 7) countries did not differ with respect to median routine first-dose measles vaccine coverage, median coverage for 3 measles campaigns, or estimated percentage of susceptible children after routine first vaccination dose and campaigns. Compared with 1-dose countries, 2-dose countries had higher median gross national income per capita (P = .002), percentage of population living in urban areas (P = .04), and female literacy (P = .01), as well as lower infant mortality (P = .007); however, no differences in time to elimination were found.
  
  
  CONCLUSIONS
  One-dose and 2-dose countries had similar times to measles elimination despite socioeconomic differences between their populations. A second routine dose might not have hastened measles elimination, because threshold immunity needed to eliminate measles was achieved with high first routine dose coverage and vaccination campaigns. Further research will be needed to determine the applicability of these findings to other regions.
authors.affiliation: National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
authors.forename: Adrianne E
authors.initials: AE
authors.lastname: Sever
authors.forename: Jeanette J
authors.initials: JJ
authors.lastname: Rainey
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Zell
authors.forename: Karen
authors.initials: K
authors.lastname: Hennessey
authors.forename: Amra
authors.initials: A
authors.lastname: Uzicanin
authors.forename: Carlos
authors.initials: C
authors.lastname: Castillo-Solórzano
authors.forename: Vance
authors.initials: V
authors.lastname: Dietz
mesh_terms: D000293:Adolescent; D002489:Central America / Q000453:epidemiology; D002648:Child; D003140:Communicable Disease Control; D004198:Disease Susceptibility; D004334:Drug Administration Schedule; D006801:Humans; D008457:Measles / Q000453:epidemiology / Q000517:prevention & control*; D008458:Measles Vaccine / Q000008:administration & dosage* / Q000276:immunology*; D009313:National Health Programs; D012307:Risk Factors; D012959:Socioeconomic Factors; D013020:South America / Q000453:epidemiology; D014611:Vaccination
chemical_list: D008458:Measles Vaccine