While the model underestimated the total number of hospitalizations, the number of critical care admissions and the mean and total length of critical care were accurate. [...] One of the major pieces of planning in the pH1N1 pandemic was the implementation of a mass vaccination campaign, which was a significant expansion of the usual seasonal influenza vaccine campaign for SHR. [...] Planning for and Implementing the Mass Immunization Campaign Upon declaration of the pandemic by the WHO, the Mass Immunization Team initiated the planning process for mass immunization in the community. [...] Objective: to immunize the public as rapidly and safely as possible (as defined by the Canadian Influenza Plan) Actions Included: • Allocating, distributing and administering the vaccine to appropriate groups and monitoring the safety and effectiveness of the program. [...] As such, the Vaccine Allocation Approval Committee (VAAC) provided consistency in distributing the available doses of vaccine among health care providers and the public in accordance with the provincial priority list and the weekly supply of vaccine available.