Sentinel Practitioner Surveillance Network (SPSN) — Influenza Vaccine Effectiveness Program

Influenza surveillance is important for controlling the spread of influenza in Ontario. The Sentinel Practitioner Surveillance Network – Influenza Vaccine Effectiveness Monitoring (SPSN) looks at influenza vaccine effectiveness to help inform Ontario’s vaccine policies. This program also contributes to a provincial, national and international lens on influenza activity including monitoring and responding to outbreaks, epidemics and pandemics, as well as vaccine strain selection.

Current Influenza Season Updates

The 2019 influenza season has started earlier than previous years in Australia, Chile, South Africa and New Zealand. During the 2019 influenza season in the southern hemisphere influenza A (H3N2) was the predominant subtype circulating in South Africa and Oceania, and influenza A(H1N1)pdm09 predominated in temperate South America (WHO, Influenza Update 346, 22 July 2019).

The seasonal influenza vaccine for this season (2019-20) in Ontario includes both subtypes of influenza A (H3N2 and H1N1pdm09), as well as both lineages of influenza B (Yamagata and Victoria), but the exact match and effectiveness can only be determined through testing. This season's High Dose trivalent influenza vaccine includes both influenza A subtypes and influenza B (Victoria lineage).



The goal of SPSN is to evaluate how well the influenza vaccine works each year. The SPSN relies on a network of primary care practitioners in each participating province to collect and submit respiratory specimens for testing and analysis. Ontario has been part of the SPSN since 2008.

How it Works

Participation in the program is voluntary. Sentinels (primary care practitioners including family physicians and nurses in the extended class/nurse practitioners) can sign up annually to be a part of the SPSN. Over the period of the program, sentinels are required to submit one to two specimens per week of patients presenting with influenza-like symptoms. Along with the specimen, sentinels complete a short questionnaire on the test requisition to provide a brief influenza immunization history of the patient. Specimens are sent to PHO’s laboratory where they are tested for influenza as part of the program. Test results, with the immunization history, are used for surveillance, as well as to estimate vaccine effectiveness.

Information generated by the SPSN is used to help inform Canada’s and Ontario’s vaccine policies, as well as assist the World Health Organization (WHO) in their vaccine strain selection process.

Ethics Review

The program received ethics board approval in all participating provinces. British Columbia, Alberta and Quebec are also participating. Recruitment for the program is conducted in collaboration with the College of Family Physicians of Canada National Research System.

We rely on sentinel practitioners to help us monitor influenza in the community setting and evaluate the performance of influenza vaccines.

When you join our study, you help to accurately measure circulating influenza strains in Ontario, including novel strains (H7N9), variant strains (H3N2v) and others. You also:

  • Help to inform Canada’s vaccination policies.
  • Help to inform the World Health Organization strain selection committee for the Northern Hemisphere.
  • Receive timely results about your patients’ diagnoses.
  • Bring valuable knowledge to your practice, including tracking of influenza activity.

Who Can Participate?

Primary care practitioners (family physician or nurse practitioner) practicing in Ontario and interested in:

  • Knowing the results of influenza testing for their patients
  • Contributing to influenza surveillance in the community
  • Understanding how the influenza vaccine works each year

Requirements for Participation


Fill out a Consent Form and send it back to us.


Following your consent, you will receive an information package with instructions and a set of influenza test kits from Public Health Ontario laboratory.


Use these test kits to collect a nasopharyngeal (preferred) or nasal swab from patients presenting to your practice within seven days of influenza-like illness (ILI) onset, as per the FluWatch ILI case definition. Specimen collection can commence as soon as you receive your collection kits and continue until the end of the current influenza season or until notified by the SPSN coordinator.


Submit an average of one to two specimens per week (20-25 in total) from your eligible patients during the study period to PHO laboratory. The laboratory will test the respiratory specimens sent for diagnosis as part of this study and send you the results within one week.*


Complete a brief questionnaire as part of the laboratory requisition form for each specimen. Together with the laboratory information and test results, these questions enable us to estimate vaccine effectiveness. It's essential that you fully complete the questionnaire. A partially completed questionnaire may result in the specimen being excluded from the vaccine effectiveness analysis. The specimen will still be tested and the results reported.

* We encourage sentinel physicians to register to for PHO’s Autofax service for a timely report of lab results. Please contact Customer Service Centre at 416-235-6556 or 1-877-604-4567 (toll free) to register.


You will be compensated at the rate of $10 per specimen sent to the laboratory with a completed short questionnaire.

How to Take Part in the Study?

Fill out a Consent Form and email it to or fax it back to Romy Olsha, Vaccine Effectiveness Coordinator at 416-596-1799.

This page contains information for sentinel physicians on collecting specimens, completing the requisition form, transporting specimens and reporting results. See the Instruction Sheet for full details.

Collecting Specimens

  • Wear appropriate PPE to protect yourself.
  • Ask patients who have copious discharge to gently clean their nose with a tissue or wash it.
  • Collect an appropriate nasopharyngeal (preferred) or nasal specimen.
  • Place the swab into the accompanying vial of universal transport medium. Break the swab at its break point so that the swab stays in the vial. Tighten the lid securely.
  • Label the vial with the patient’s full name and date of birth. Place the specimen in the biohazard bag provided and seal the specimen pocket of the bag using the adhesive strip.
  • Refrigerate at 4°C until transported to the lab.

Completing the Requisition Form

Complete all fields of the SPSN – Vaccine Effectiveness Test Requisition Form provided:

  • Fill out one form for each submitted specimen.
  • Under clinician/referring laboratory, enter the full name and billing address of the practitioner/facility to which the final report will be sent.
  • Enter the specimen collection date in the appropriate box.
  • Complete the questionnaire to help assess vaccine effectiveness in protecting against laboratory-confirmed influenza.
  • For each specimen, place the completed form in the outside pocket of each biohazard bag.
  • Use one biohazard bag for each specimen and the accompanying completed requisition form.

Transporting Specimens

  • Submit SPSN specimens to PHO’s laboratory via your usual lab submission route.

Reporting Results

Results will be reported directly to the submitter’s office. You will receive results from the Laboratory Information System using the AutoFax system. To register for AutoFax, call PHO’s Customer Service Centre at 416-235-6556 or 1-877-604-4567.

1. How many respiratory specimens should be taken by each sentinel practitioner?

This may vary, but based on statistical power calculations and experience from several influenza seasons, it is anticipated that an average of one to two specimens per week may be submitted by each sentinel practitioner over the course of the study period for a total of 20-25 specimens per season. In the national collaboration between British Columbia, Alberta, Ontario and Quebec, we are aiming for a total of 3,000 respiratory specimens as part of this study.

2. When should I start taking specimens from patients presenting with symptoms of influenza-like illness this year?

You can start submitting specimens as soon as you receive the information package and testing kits.

3. Which patients are eligible for inclusion?

Any patient who is a resident of Ontario, who presents in your practice with symptoms of an influenza-like illness (ILI) (as per the FluWatch definition) within one week of ILI symptom onset.
You should collect a nasopharyngeal or nasal swab using the test kits for influenza testing.

You will be notified if specimen collection for the purpose of this study will change. Please note that it is important that you collect respiratory specimens from patients who are residents of Ontario and who are presenting within seven days of ILI onset, whether they received the influenza vaccine or not.

4. Should I submit SPSN specimens to the laboratory where I usually send respiratory specimens?

Yes. Sentinels can submit SPSN specimens to PHO Laboratory via their routine lab submission process. Specimens will be directed to PHO by your lab. Please ensure that a fully completed SPSN requisition is submitted with the specimen.

5. Will I be compensated for my time?

Yes. Your time, effort and participation are much appreciated. Participating sentinel practitioners will be compensated $10 for each specimen submitted with a completed SPSN-specific requisition. Reimbursement will be made at the end of each period.

6. Has this study received ethics approval and if so, what special ethics requirements are there?

The SPSN’s methodology has been reviewed by ethics boards in each participating province every year since 2004. This means that separate ethics review and approval has been granted in each of British Columbia, Alberta, Ontario and Quebec (four separate reviews). For the 2019-2020 season, ethics approval was granted in the Fall of 2019. As part of the program, sentinel physicians and nurse practitioners are required to inform their eligible patients and elicit verbal consent to participate through specimen collection and questionnaire completion. A verbal consent script has been drafted by SPSN investigators for this purpose and is included with the study material sent to consenting sentinels.

7. Who else participates in this study?

In each participating province, a team of epidemiologists and laboratory investigators has been established. These investigators have been working collaboratively for several years and Ontario investigators and sentinel physicians will again join that team of provincial investigators this season.

8. How will vaccine effectiveness be calculated?

Vaccine effectiveness (VE) against laboratory confirmed influenza is calculated by SPSN researchers based on a case control design. Using the laboratory results (either positive or negative for influenza) and the answers to the questions accompanying the laboratory requisition (e.g., recent influenza immunization history), vaccine status is compared for those with and without influenza. The program is based on the understanding that not everyone with influenza-like illness will have influenza. Those who test positive for influenza are counted as cases, whereas those who test negative for influenza become the controls. Immunization rates among these two groups are used for VE estimation.

9. Where will this analysis be done nationally and how will confidentiality be preserved?

Since 2004, an overall vaccine effectiveness result has been calculated for all participating provinces combined nationally through statistical analysis at the British Columbia Centre for Disease Control (BCCDC).

Data from Quebec, Ontario, and Alberta that are shared with BCCDC in calculating this combined estimate do not include any personal identifiers and conditions, as specified by ethics boards. Absolutely no personal identifying information will be transmitted. Only the influenza test result and relevant epidemiologic information provided on the requisition are shared for the sole purpose of calculating an aggregate vaccine effectiveness result. At each level, all data is stored in a secure and locked facility. Dr. Danuta Skowronski, principal investigator, is located at the BCCDC.

10. Do I need special equipment for the study?

You will need:

11. Where can I get more information about what else is circulating in my area?

Please refer to the Ontario Respiratory Pathogen Bulletin for more information.

12. How do I receive results for specimens I submitted?

In order to reduce the turnaround time and increase the efficiency of testing and reporting, results will be reported automatically by the Laboratory Information System using the AutoFax system. To register for AutoFax, please contact the Toronto Public Health Laboratory’s Customer Service Centre at 416-235-6556 or 1-877-604-4567.

A list of recent publications by the SPSN:

  1. Skowronski Danuta M, Sabaiduc Suzana, Leir Siobhan, Rose Caren, Zou Macy, Murti Michelle, Dickinson James A, Olsha Romy, Gubbay Jonathan B, Croxen Matthew A, Charest Hugues, Bastien Nathalie, Li Yan, Jassem Agatha, Krajden Mel, De Serres Gaston. Paradoxical clade- and age-specific vaccine effectiveness during the 2018/19 influenza A(H3N2) epidemic in Canada: potential imprint-regulated effect of vaccine (I-REV). Euro Surveill. 2019;24(46):pii=1900585.
  2. Skowronski Danuta MLeir SiobhanSabaiduc SuzanaMurti MichelleDickinson James AOlsha RomyGubbay Jonathan BCroxen Matthew ACharest HuguesChan TracyBastien NathalieLi YanKrajden MelDe Serres Gaston. Interim estimates of 2018/19 vaccine effectiveness against influenza A(H1N1)pdm09, Canada, January 2019. Euro Surveill. 2019;24(4):pii=1900055.
  3. Skowronski DM, Chambers C, De Serres G, Dickinson JA, Winter AL, Hickman R, Chan T, Jassem AN, Drews SJ, Charest H, Gubbay JB, Bastien N, Li Y, Krajden M. Early season co-circulation of influenza A(H3N2) and B(Yamagata): interim estimates of 2017/18 vaccine effectiveness, Canada, January 2018. Euro Surveill. 2018 Feb;23(5). doi: 10.2807/1560-7917.ES.2018.23.5.18-00035.
  4. Skowronski DM, Chambers C, Sabaiduc S, Dickinson JA, Winter AL, De Serres G, Drews SJ, Jassem A, Gubbay JB, Charest H, Balshaw R, Bastien N, Li Y, Krajden M. Interim estimates of 2016/17 vaccine effectiveness against influenza A(H3N2), Canada, January 2017. Euro Surveill. 2017; 22(6). doi: 10.2807/1560-7917.ES.2017.22.6.30460
  5. Chambers C, Skowronski DM, Sabaiduc S, Winter AL, Dickinson JA, De Serres G, Gubbay JB, Drews SJ, Martineau C, Eshaghi A, Krajden M, Bastien N, Li Y. Interim estimates of 2015/16 vaccine effectiveness against influenza A(H1N1)pdm09, Canada, February 2016. Euro Surveill. 2016;21(11). doi: 10.2807/1560-7917.ES.2016.21.11.30168.
  6. Skowronski DM, Chambers C, Sabaiduc S, De Serres G, Winter AL, Dickinson JA, Krajden M, Gubbay JB, Drews SJ, Martineau C, Eshaghi A, Kwindt TL, Bastien N, Li Y. A Perfect Storm: Impact of Genomic Variation and Serial Vaccination on Low Influenza Vaccine Effectiveness during the 2014-2015 Season. Clin Infect Dis. 2016 Jul 1;63(1):21-32. doi: 10.1093/cid/ciw176. Epub 2016 Mar 29.
  7. Skowronski DM, Sabaiduc S, Chambers C, Eshaghi A, Gubbay JB, Krajden M, Drews SJ, Martineau C, De Serres G, Dickinson JA, Winter AL, Bastien N, Li Y. Mutations acquired during cell culture isolation may affect antigenic characterisation of influenza A(H3N2) clade 3C.2a viruses. Euro Surveill. 2016;21(3):30112. doi: 10.2807/1560-7917.ES.2016.21.3.30112.
  8. Skowronski DM, Chambers C, Sabaiduc S, De Serres G, et al. Integrated Sentinel Surveillance Linking Genetic, Antigenic, and Epidemiologic Monitoring of Influenza Vaccine-Virus Relatedness and Effectiveness During the 2013-2014 Influenza Season. J Infect Dis. 2015 Mar 17. pii: jiv177.
  9. Skowronski DM, Chambers C, Sabaiduc S, De Serres G, Dickinson JA, Winter AL, Drews SJ, Fonseca K, Charest H, Gubbay JB, Petric M, Krajden M, Kwindt TL, Martineau C, Eshaghi A, Bastien N, Li Y. Interim estimates of 2014/15 vaccine effectiveness against influenza A(H3N2) from Canada’s Sentinel Physician Surveillance Network, January 2015. Euro Surveill. 2015;20(4):pii=21022.
  10. Skowronski DM, Janjua NZ, De Serres G, Sabaiduc S, Eshaghi A, et al. (2014) Low 2012–13 Influenza Vaccine Effectiveness Associated with Mutation in the Egg-Adapted H3N2 Vaccine Strain Not Antigenic Drift in Circulating Viruses. PLoS ONE 9(3): e92153. doi:10.1371/journal.pone.0092153
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Updated 22 Nov 2019