1038. Epidemiology of Influenza Viruses in Canada over the 2011/2012 to 2013/2014 Seasons: A Study from the Serious Outcomes Surveillance (SOS) Network of the Canadian Immunization Research Network (CIRN)
Session: Poster Abstract Session: Adult Viral Infection
Friday, October 6, 2017
Room: Poster Hall CD
  • CIRN_SOS_Epi of Flu viruses_19Sept2017.pdf (302.2 kB)
  • Background: Influenza virus activity varies seasonally and within season. Epidemiology of serious influenza outcomes is contingent on the prevalent circulating strain/s and susceptible age group/s. Given the strain variability over the 2011/12 through 2013/14 seasons in Canada, this study examined the clinical and epidemiological profiles of different influenza strains causing adult hospitalizations.

    Methods: During these three influenza seasons, the Serious Outcomes Surveillance (SOS) Network of the Canadian Immunization Research Network (CIRN) enrolled adults hospitalized with acute respiratory illness across Canada. Nasopharyngeal swabs (NPs) from influenza cases were tested for strain characterization using real-time reverse transcriptase polymerase chain reaction (rtRT-PCR). A primary assay differentiated A and B influenza viruses. Subsequently, influenza A viruses were subtyped as H1N1 or H3N2, and influenza B lineages were differentiated as Victoria or Yamagata. Laboratory results were compared with patient demographic data and clinical outcomes.

    Results: Over three consecutive influenza seasons, 3394 cases of hospitalized acute respiratory illness were laboratory-confirmed as influenza. At 72.4%, influenza A was predominant across all seasons, while influenza B caused 27.6%. Most of the influenza A cases were due to H3N2 (58.7%), while H1N1 accounted for 41.3%. For influenza B, the Yamagata lineage was predominant at 88.4% whereas the Victoria lineage accounted for 11.6%. Outcome analyses are presented for each influenza A subtype and influenza B lineage, overall and per season. Considering serious outcomes in patients ≥65, higher proportions of patients hospitalized with the H1N1 strain experienced intensive care unit (ICU) admission and need for mechanical ventilation, while higher proportions of patients hospitalized with B/Yamagata and H3N2 died within 30 days of admission.

    Conclusion: Comprehensive collection of surveillance data paired with NP specimens by the CIRN SOS Network was conducive to broader understanding of influenza strain activity and associated outcomes at the subtype and lineage level. This data is important to make informed recommendations for use of multicomponent influenza vaccines.

    May Elsherif, MD1, Todd Hatchette, MD FRCPC2, Jason Leblanc, PhD1, Lingyun Ye, MSc1, Melissa K Andrew, MD, PhD1, Ardith Ambrose, RN1, Guy Boivin, MD, MSc3, William R. Bowie, MD, FRCPC, FIDSA4, Karen Green, MSc, RN5, Kevin Katz, MD, CM, MSc, FRCPC6, Mark Loeb, MD, MSc7, Donna Mackinnon-Cameron, MMath1, Anne Mccarthy, MD, MSc8, Janet McElhaney, MD9, Allison Mcgeer, MD, MSc5, Michaela Nichols, MSc1, Jeff Powis, MD, MSc, FRCPC10, David Richardson, MD11, Makeda Semret, MD12, Daniel Smyth, MD, FRCPC13, Sylvie Trottier, MD, PhD3, Louis Valiquette, MD, MSc, FRCPC14, Duncan Webster, MD15 and Shelly McNeil, MD, FRCPC, FIDSA1, (1)Canadian Center for Vaccinology, IWK Health Centre and Nova Scotia Health Authority, Dalhousie University, Halifax, NS, Canada, (2)Nova Scotia Health Authority, Dalhousie University, Halifax, NS, Canada, (3)Centre Hospitalier Universitaire de Quebec, Quebec City, QC, Canada, (4)Division of Infectious Diseases, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, (5)Mount Sinai Hospital, Toronto, ON, Canada, (6)North York General Hospital, Toronto, ON, Canada, (7)McMaster University, Hamilton, ON, Canada, (8)The Ottawa Hospital, Ottawa, ON, Canada, (9)Health Sciences North Research Institute, Sudbury, ON, Canada, (10)Michael Garron Hospital, Toronto, ON, Canada, (11)William Osler Health System, Brampton, ON, Canada, (12)McGill University, Montreal, QC, Canada, (13)The Moncton Hospital, Moncton, NB, Canada, (14)Microbiology and Infectious Disease, Université de Sherbrooke, Sherbrooke, QC, Canada, (15)Saint John Regional Hospital, Dalhousie University, Saint John, NB, Canada


    M. Elsherif, Canadian Institutes of Health Research: Investigator , Research grant
    Public Health Agency of Canada: Investigator , Research grant
    GSK: Investigator , Research grant

    T. Hatchette, GSK: Grant Investigator , Grant recipient
    Pfizer: Grant Investigator , Grant recipient
    Abbvie: Speaker for a talk on biologics and risk of TB reactivation , Speaker honorarium

    J. Leblanc, None

    L. Ye, None

    M. K. Andrew, GSK: Grant Investigator , Research grant
    Pfizer: Grant Investigator , Research grant
    Sanofi-Pasteur: Grant Investigator , Research grant

    A. Ambrose, None

    G. Boivin, None

    W. R. Bowie, None

    K. Green, None

    K. Katz, None

    M. Loeb, None

    D. Mackinnon-Cameron, None

    A. Mccarthy, None

    J. McElhaney, GSK Vaccines: Scientific Advisor , Speaker honorarium

    A. Mcgeer, Hoffman La Roche: Investigator , Research grant
    GSK: Investigator , Research grant
    Sanofi Pasteur: Investigator , Research grant

    M. Nichols, None

    J. Powis, Merck: Grant Investigator , Research grant
    GSK: Grant Investigator , Research grant
    Roche: Grant Investigator , Research grant
    Synthetic Biologicals: Investigator , Research grant

    D. Richardson, None

    M. Semret, GSK: Investigator , Research grant
    Pfizer: Investigator , Research grant

    D. Smyth, None

    S. Trottier, Canadian Institutes of Health Research: Investigator , Research grant

    L. Valiquette, GSK: Investigator , Research grant

    D. Webster, None

    S. McNeil, GSK: Contract Clinical Trials and Grant Investigator , Research grant
    Merck: Contract Clinical Trials and Speaker's Bureau , Speaker honorarium
    Novartis: Contract Clinical Trials , No personal renumeration
    Sanofi Pasteur: Contract Clinical Trials , No personal renumeration

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 4th with the exception of research findings presented at the IDWeek press conferences.