title: Assessment of the role of international travel and unauthorized immigration on measles importation to the United States.
abstract: BACKGROUND
  Concerns have been raised about unauthorized immigrants importing measles to the United States (US). This potential risk has not been rigorously evaluated nor compared with the potential risk of measles importation by US residents traveling internationally or international travellers coming to the US. We compared the potential risk of measles importation from each of these populations.
  
  
  METHODS
  Using a cross-sectional, ecological design, we compared country-level measles vaccination and incidence data, for top (i) US resident international travel destinations, (ii) US-bound international travellers' home countries and (iii) home countries of unauthorized immigrants to the US.
  
  
  RESULTS
  In 2014, US residents made 52.5 million trips to one of the top 10 international destinations. Five of these countries (10,958,000 US resident trips) had average first-dose measles vaccine coverage below 90%, and five (9,881,000 US resident trips) had average measles incidence over 1 case/100,000 population. Two of the 10 top US-bound international travellers' home countries (5,597,259 international visitors) had average first-dose measles vaccine coverage below 90%, whereas five (13,333,545 international visitors) had average annual measles incidence over 1 case/100,000 population). In 2012, of 11.2 million unauthorized immigrants living in the US, 8.9 million (79.0%) were born in one of the top 10 unauthorized immigrant home countries. Four of those countries had average first-dose measles vaccine coverage below 90% (1.3 million unauthorized immigrants), whereas three of these countries had average measles incidence over 1 case/100,000 population (950,000 unauthorized immigrants). Overall, there are 10 times more annual US visitors to high measles incidence countries than there are unauthorized immigrants in the US from high measles incidence countries.
  
  
  CONCLUSIONS
  Efforts to prevent reestablishment of indigenous measles transmission in the US should focus on evidence-based risk assessments, highlighting a greater potential measles importation risk of from US residents travelling internationally than unauthorized immigrants coming to the US.
authors.affiliation: Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, Emory Vaccine Center, Emory University, Atlanta, GA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Bednarczyk
authors.affiliation: Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA and.
authors.forename: Paulina A
authors.initials: PA
authors.lastname: Rebolledo
authors.affiliation: Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, Emory Vaccine Center, Emory University, Atlanta, GA, Department of Pediatrics, Schools of Medicine, Emory University, Atlanta, GA, USA.
authors.forename: Saad B
authors.initials: SB
authors.lastname: Omer
mesh_terms: D064870:Air Travel; D003430:Cross-Sectional Studies; D006801:Humans; D015994:Incidence; D008457:Measles / Q000453:epidemiology* / Q000517:prevention & control*; D008458:Measles Vaccine / Q000627:therapeutic use*; D018570:Risk Assessment; D000069756:Undocumented Immigrants; D014481:United States; D014611:Vaccination / Q000706:statistics & numerical data
chemical_list: D008458:Measles Vaccine
keywords: Measles; air travel.; border crossing; immigration; travel