title: Measles outbreaks in the UK, is it when and where, rather than if? A database cohort study of childhood population susceptibility in Liverpool, UK.
abstract: There was a large outbreak of measles in Liverpool, UK, in 2012-2013, despite measles, mumps and rubella (MMR) immunisation uptake rates that were higher than the national average. We estimated measles susceptibility of a cohort of children born in Liverpool between 1995 and 2012 to understand whether there was a change in susceptibility before and after the outbreak and to inform vaccination strategy.
  
  
  
  Retrospective cohort study.
  
  
  
  The city of Liverpool, North West UK.
  
  
  
  All children born in Liverpool (72 101) between 1995 and 2012 inclusive who were identified using the Child Health Information System (CHIS) and were still resident within Liverpool in 2014.
  
  
  
  We estimated cohort age-disaggregated and neighbourhood-disaggregated measles susceptibility according to WHO thresholds before and after the outbreak for children aged 1-17 years.
  
  
  
  Susceptibility to measles was above WHO elimination thresholds before and after the measles outbreak in the 10+ age group. The proportion of children susceptible before and after outbreak, respectively: age 1-4 years 15.0% before and 14.9% after; age 5-9 years 9.9% before and 7.7% after; age 10+ years 8.6% before and 8.5% after. Despite an intensive MMR immunisation catch-up campaign after the 2012-2013 measles outbreak, the overall proportion of children with no MMR remains high at 6.1% (4390/72 351). Across all age groups and before and after the outbreak, measles susceptibility was clustered by neighbourhood, with deprived areas having the greatest proportion of susceptible children.
  
  
  
  The risk of sustained measles outbreaks remains, especially as large pools of susceptible older children will start leaving secondary education and continue to aggregate in higher education, employment and other community settings and institutions resulting in the potential for a propagated measles outbreak.
authors.affiliation: Cheshire and Merseyside Health Protection Team, Public Health England North West, Liverpool, UK.
authors.forename: Alex
authors.initials: A
authors.lastname: Keenan
authors.affiliation: Cheshire and Merseyside Health Protection Team, Public Health England North West, Liverpool, UK.
authors.forename: Sam
authors.initials: S
authors.lastname: Ghebrehewet
authors.affiliation: Field Epidemiology Services, Public Health England, Liverpool, UK.
authors.forename: Roberto
authors.initials: R
authors.lastname: Vivancos
authors.affiliation: NHS England, Liverpool, UK.
authors.forename: Dan
authors.initials: D
authors.lastname: Seddon
authors.affiliation: Cheshire and Merseyside Health Protection Team, Public Health England North West, Liverpool, UK.|Department of Public Health and Policy, University of Liverpool, Liverpool, UK.|Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: MacPherson
authors.affiliation: Department of Public Health and Policy, University of Liverpool, Liverpool, UK.|Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK.
authors.forename: Daniel
authors.identifier: 0000-0002-9770-0163
authors.initials: D
authors.lastname: Hungerford
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D004198:Disease Susceptibility / Q000453:epidemiology; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D017589:Immunization Programs / Q000706:statistics & numerical data; D007223:Infant; D008297:Male; D008457:Measles / Q000453:epidemiology* / Q000517:prevention & control; D022542:Measles-Mumps-Rubella Vaccine; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data; D011446:Prospective Studies; D012189:Retrospective Studies
chemical_list: D022542:Measles-Mumps-Rubella Vaccine
keywords: EPIDEMIOLOGY; PUBLIC HEALTH