1. GM Johnston (corresponding author) School of Health Administration, Dalhousie University, and Surveillance and Epidemiology Unit, Cancer Care Nova Scotia, Bethune 568, 1276 South Street, Halifax, Nova Scotia, Canada B3H 2Y9;
2. Health Canada, Centre for Vaccine Evaluation, Biologics and Genetic Therapies Directorate, Ottawa, Ontario, Canada
3. University of British Columbia, Centre for Health Services and Policy Research, Vancouver, British Columbia, Canada
4. Department of Medicine, Dalhousie University, and Palliative Medicine, Capital Health, Halifax, Nova Scotia, Canada.