Dr. Kellner is a paediatrician and subspecialist in paediatric infectious diseases and clinical epidemiology. His research focuses on vaccine preventable infections, working closely with experts from clinical medicine and public health across Canada and globally. Between 2008-2018 he was the Head of Paediatrics at the University of Calgary and the Calgary Zone of Alberta Health Services. Dr. Kellner has served on the Alberta Advisory Committee on Immunization since 2002 and was Chair for a decade. He is a member of the federal COVID-19 Immunity Task Force Leadership Group and Co-Chair of the Task Force’s Field Studies Working Party. He is also leading the multi-faceted Alberta Childhood COVID-19 Cohort (AB3C) Study, is an investigator with the Canadian Immunization Research Network, and is Co-principle investigator for Alberta on the Canadian National Vaccine Safety Network (CANVAS) COVID-19 vaccine project.