Assessing safety of Ontario's publicly funded MMR and MMRV immunization programs, 2012 to 2016.

Background: The combined measles, mumps, rubella (MMR) and measles, mumps, rubella, and varicella (MMRV) vaccines are part of Ontario's routine immunization schedule.

Objective: To assess adverse events following immunization (AEFIs) reported in Ontario following administration of MMR and MMRV vaccines between 2012 and 2016.

Methods: Reports of AEFIs were extracted from the provincial surveillance database on May 9, 2017.