200405 - An observational retrospective database analysis to estimate the risk of Multiple Sclerosis (MS) following vaccination with Arepanrix™ in Manitoba, Canada

Study type

• Study topic:
  Disease /health condition

  Human medicinal product
• Study type:
  Non-interventional study
• Scope of the study:
  Assessment of risk minimisation measure implementation or effectiveness
• Data collection methods:
  Secondary use of data

Non-interventional study

• Non-interventional study design:
  Cohort

Study drug and medical condition

• Medicinal product name:
  AREPANRIX
• Medical condition to be studied:
  Multiple sclerosis

Population studied

• Short description of the study population:
  Adults and children above 6 months of age (at the time of vaccination) who normally resided in Manitoba and had been registered with MH for at least 1 year before the enrolment period. The entire population of Manitoba was considered for inclusion.
• Age groups:
  • Infants and toddlers (28 days – 23 months)
  • Children (2 to < 12 years)
  • Adolescents (12 to < 18 years)
  • Adults (18 to < 46 years)
  • Adults (46 to < 65 years)
  • Adults (65 to < 75 years)
  • Adults (75 to < 85 years)
  • Adults (85 years and over)
• Estimated number of subjects:
  1

Study design details

• Main study objective:
  To assess whether administration of Arepanrix™ was associated with an increased risk of incident MS.
• Outcomes:
  Occurrence of MS during the period of one year following administration of Arepanrix™ among an exposed cohort and during an equivalent time period in the unexposed cohort (15 September 2009 to 15 March 2010). Occurrence of MS from administration of Arepanrix™ until 31 December 2012 and occurrence of demyelinating events which do not ultimately lead to a diagnosis of MS (i.e. never have a diagnostic claim for MS) during one year following administration of Arepanrix™ and until 31 December 2012, respectively, among an exposed cohort and during equivalent time periods in the unexposed cohort.
• Data analysis plan:
  The study is a retrospective analysis of population-based cohorts of subjects, whose vaccination status and health events before and after vaccination are recorded in various MH administrative databases. A propensity-score (PS) matched cohort analysis will be conducted using de-identified records obtained by linking the electronic database of the Manitoba Immunization Monitoring System (MIMS) with the hospital, physician and prescription claims databases of MH.PS methods are one approach to constructing more comparable groups with respect the distribution of important disease (or outcome) predictors (confounders) to reduce biases due to lack of random treatment assignment in observational studies. Each vaccinated individual will be matched to an individual who did not receive any influenza vaccines during the study period.Cox proportional hazard models, with stratification on the PS matched pairs, will be used to estimate relative risks (hazards ratios) associated with vaccination.