Influenza Vaccine Effectiveness Study

Since 2006, TARRANT has partnered with the BC Center for Disease Control, the National Microbiology Lab, and provincial programs from Ontario and Quebec to determine influenza vaccine effectiveness. Through a test negative incident case control design, patients presenting with ILI are recruited by sentinels across the 4 provinces in the SPSN (Sentinel Practitioner Surveillance Network) and tested for laboratory-confirmed influenza. This data is combined with their vaccination history to determine vaccine effectiveness.

Some achievements so far

• Better understanding of variability in vaccine effectiveness
• Timely mid-season reporting (See publication link)
• Informing WHO vaccine selection
• Repeat vaccination effects
• Birth cohort effects on vaccine effectiveness
• Sex effects on vaccine effectiveness

We usually report a mid-season estimate of vaccine effectiveness to measure its value against the initial influenza peak of the winter season. This produces a result that can be used by WHO to choose the next year’s vaccine. At end of season, we measure vaccine effectiveness against the usually 2 or 3 sub-epidemics of influenza that occur through the winter.