This observational, retrospective, propensity-score matched cohort study using the Manitoba Immunization Monitoring System (MIMS) and the hospital, physician, and prescription claims databases of the Manitoba Health (MH) Database System will assess if Arepanrix™ vaccination during the 2009 pandemic was associated with an increased risk of multiple sclerosis (MS) and other demyelinating conditions not ultimately leading to a multiple sclerosis diagnosis in Manitoba, Canada.
The data will be collected form the following linked databases:
* Manitoba Health (MH) administrative databases
* Manitoba Immunization Monitoring System (MIMS)
* Manitoba Health Population Registry (MHPR)
* Drug Program Information Network (DPIN)
* Hospital Abstract Database
* The Medical Services database
