CPHA Canvax

British Columbia Centre for Disease Control

Project Title:  Influenza-like Illness (ILI) Sentinel Practitioner Surveillance Network (SPSN): Virus and Vaccine Effectiveness Monitoring
Funding Recipient: British Columbia Centre for Disease Control (BCCDC)
Project Contact:  Dr. Danuta Skowronski – Epidemiology Lead (Danuta.Skowronski@bccdc.ca)
Project Period:  March 20th, 2017 – March 31th, 2018

About the Project

Influenza is a significant burden to the clinical health care system and represents a major societal cost in terms of winter absenteeism. In order for the influenza immunization program to deliver the best protection and return on investment, and to develop improved vaccine options, researchers need to know how well the current vaccines perform and why they may be suboptimal in some seasons. As such, knowing how well the reformulated influenza vaccine protects against the rapidly evolving influenza virus each year is extremely relevant. The goal of the Canadian Sentinel Practitioner Surveillance Network (SPSN) with headquarters at the BCCDC, is to monitor circulating influenza viruses and the effectiveness of the annually reformulated influenza vaccine each season to help inform health policy and the influenza immunization strategy.


The ultimate goal of the national influenza immunization program is to reduce the morbidity and mortality of influenza-associated disease. Monitoring influenza vaccine effectiveness is fundamental to assessing progress and the beneficial impact of influenza vaccination in achieving those goals. Furthermore, a better understanding of the agent-host factors contributing to influenza vaccine performance is required to guide updates and improvements to currently available seasonal vaccines and to inform the future development of next-generation or universal influenza vaccines.


The study objectives for the Canadian SPSN for the 2016-17 season included:

  • To derive component-specific vaccine effectiveness against medically-attended, laboratory-confirmed influenza.
  • To conduct detailed genotypic and phenotypic characterization of circulating viruses to assess clade-specific vaccine effectiveness estimation and vaccine relatedness in support of vaccine effectiveness interpretation.
  • To explore agent-host factors that may influence current season’s vaccine effectiveness, including the effects of prior season vaccination.
  • To develop a summary report/publication on systematic community-based vaccine effectiveness in Canada for the 2016-17 influenza season.
  • To share and enhance knowledge related to vaccine effectiveness estimates for the 2016/17 season in Canada through health promotion/education/communication stakeholders and public health networks, bulletins, distribution lists and media messaging.

The challenge that the project addresses

Each year, the seasonal influenza epidemic causes a significant disease burden. Because of evolutionary changes in circulating influenza viruses, the seasonal influenza vaccine must be reviewed annually and reformulated as needed to protect against the current epidemic strain. Each year, influenza vaccine is administered within a 6-8 week period to about 30% of the Canadian population (~12 million doses). It is among the most intense of all immunization programs in Canada, often accompanied by substantial political and media interest. However, the effectiveness of the annually revised influenza vaccines is unknown, necessitating real-time monitoring and evaluation each season to inform our national immunization strategy and adjunct protective measures.

Lessons learned

The annually revised influenza vaccine requires that study activities must be renewed each year to monitor influenza vaccine performance. Lower vaccine effectiveness requires larger sample size to demonstrate precise and statistically significant vaccine effect/benefit. Ongoing funding is required to maintain and enhance the Canadian SPSN infrastructure each season. Any enhancements to the existing network to expand sentinel recruitment and retention; target recruitment of certain population sub-groups; or engage in further promotional activities are contingent upon sustained and enhanced funding, currently being sought for subsequent seasons.  

About the British Columbia Centre for Disease Control

The BCCDC, part of the Provincial Health Services Authority, is the lead provincial agency responsible for communicable disease prevention and control in British Columbia. The BCCDC provides provincial and national leadership in public health through surveillance, detection, prevention and consultation. The BCCDC serves as the central headquarters for the Canadian SPSN and is responsible for national project coordination, data processing and analysis, correlation of vaccine effectiveness with enhanced genetic characterization of vaccine-virus relatedness, and manuscript preparation and knowledge translation. Since 2004, the Canadian SPSN, currently comprised of sentinel practitioners in Canada’s four most populous provinces (British Columbia, Alberta, Ontario, and Quebec), has monitored circulating influenza viruses and effectiveness of the annually reformulated influenza vaccine. It is the only community-based system to annually monitor vaccine effectiveness against medically-attended, laboratory-confirmed influenza in Canada—providing estimates of vaccine protection that are most relevant to the vast majority of Canadian influenza vaccine recipients who are not at high risk of hospitalization but who receive influenza vaccine to avoid a miserable illness and/or to prevent passing the infection on to others.


Last Reviewed: October 16, 2018