title: A novel approach to evaluating the UK childhood immunisation schedule: estimating the effective coverage vector across the entire vaccine programme.
abstract: BACKGROUND
  The availability of new vaccines can prompt policy makers to consider changes to the routine childhood immunisation programme in the UK. Alterations to one aspect of the schedule may have implications for other areas of the programme (e.g. adding more injections could reduce uptake of vaccines featuring later in the schedule). Colleagues at the Department of Health (DH) in the UK therefore wanted to know whether assessing the impact across the entire programme of a proposed change to the UK schedule could lead to different decisions than those made on the current case-by-case basis. This work is a first step towards addressing this question.
  
  
  METHODS
  A novel framework for estimating the effective coverage against all of the diseases within a vaccination programme was developed. The framework was applied to the current (August 2015) UK childhood immunisation programme, plausible extensions to it in the foreseeable future (introducing vaccination against Meningitis B and/or Hepatitis B) and a "what-if" scenario regarding a Hepatitis B vaccine scare that was developed in close collaboration with DH.
  
  
  RESULTS
  Our applications of the framework demonstrate that a programme-view of hypothetical changes to the schedule is important. For example, we show how introducing Hepatitis B vaccination could negatively impact aspects of the current programme by reducing uptake of vaccines featuring later in the schedule, and illustrate that the potential benefits of introducing any new vaccine are susceptible to behaviour changes affecting uptake (e.g. a vaccine scare). We show how it may be useful to consider the potential benefits and scheduling needs of all vaccinations on the horizon of interest rather than those of an individual vaccine in isolation, e.g. how introducing Meningitis B vaccination could saturate the early (2-month) visit, thereby potentially restricting scheduling options for Hepatitis B immunisation should it be introduced to the programme in the future.
  
  
  CONCLUSIONS
  Our results demonstrate the potential benefit of considering the programme-wide impact of changes to an immunisation schedule, and our framework is an important step in the development of a means for systematically doing so.
authors.affiliation: Clinical Operational Research Unit, University College London, 4 Taviton Street, London, WC1H 0BT, UK. sonya.crowe@ucl.ac.uk.
authors.forename: Sonya
authors.initials: S
authors.lastname: Crowe
authors.affiliation: Clinical Operational Research Unit, University College London, 4 Taviton Street, London, WC1H 0BT, UK. m.utley@ucl.ac.uk.
authors.forename: Martin
authors.initials: M
authors.lastname: Utley
authors.affiliation: Department of Health, Area 330, Wellington House, 133-155 Waterloo Road, London, SE1 8UG, UK. guy.walker@dh.gsi.gov.uk.
authors.forename: Guy
authors.initials: G
authors.lastname: Walker
authors.affiliation: Clinical Operational Research Unit, University College London, 4 Taviton Street, London, WC1H 0BT, UK. j.panovska-griffiths@ucl.ac.uk.
authors.forename: Jasmina
authors.initials: J
authors.lastname: Panovska-Griffiths
authors.affiliation: Department of Health, Area 330, Wellington House, 133-155 Waterloo Road, London, SE1 8UG, UK. peter.grove@dh.gsi.gov.uk.
authors.forename: Peter
authors.initials: P
authors.lastname: Grove
authors.affiliation: Clinical Operational Research Unit, University College London, 4 Taviton Street, London, WC1H 0BT, UK. c.pagel@ucl.ac.uk.
authors.forename: Christina
authors.initials: C
authors.lastname: Pagel
mesh_terms: D002648:Child; D002675:Child, Preschool; D017325:Hepatitis B Vaccines; D006801:Humans; D017589:Immunization Programs / Q000458:organization & administration; D007115:Immunization Schedule; D007117:Immunization, Secondary; D010567:Pertussis Vaccine; D013745:Tetanus Toxoid; D006113:United Kingdom; D014611:Vaccination / Q000706:statistics & numerical data
chemical_list: D017325:Hepatitis B Vaccines; D010567:Pertussis Vaccine; D013745:Tetanus Toxoid