Monitors opposed occasions following immunization through the immunization surveillance system and stories to thenationaland global security surveillance techniques. If these events happen, authorities investigate to identify whether or not the vaccine is immediately responsible for the adverse event. Sometimes medical events occur within a few days of vaccination but usually are not associated to the vaccine. If required, a vaccine can be withdrawn from the market and never used if there is a concern of hurt. Health Canada can even issue warnings about particular risks so as to inform individuals.