title: Examining Ontario's universal influenza immunization program with a multi-strain dynamic model.
abstract: Seasonal influenza imposes a significant worldwide health burden each year. Mathematical models help us to understand how changes in vaccination affect this burden. Here, we develop a new dynamic transmission model which directly tracks the four dominant seasonal influenza strains/lineages, and use it to retrospectively examine the impact of the switch from a targeted to a universal influenza immunization program (UIIP) in the Canadian province of Ontario in 2000. According to our model results, averaged over the first four seasons post-UIIP, the rates of influenza-associated health outcomes in Ontario were reduced to about half of their pre-UIIP values. This is conservative compared to the results of a study estimating the UIIP impact from administrative data, though that study finds age-specific trends similar to those presented here. The strain interaction in our model, together with its flexible parameter calibration scheme, make it readily extensible to studying scenarios beyond the one explored here.
authors.affiliation: Medical Division, GlaxoSmithKline Inc., 7333 Mississauga Road, Mississauga, ON, Canada L5N 6L4; Department of Mathematics & Statistics, University of Guelph, 50 Stone Road East, Guelph, ON, Canada N1G 2W1. Electronic address: edward.w.thommes@gsk.com.
authors.forename: E W
authors.initials: EW
authors.lastname: Thommes
authors.affiliation: Sanofi Pasteur, 1755 Steeles Avenue West, Toronto, ON, Canada M2R 3T4; Lesli Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, ON, Canada M5S 3M2.
authors.forename: A
authors.initials: A
authors.lastname: Chit
authors.affiliation: GlaxoSmithKline Inc., Avenue Fleming 20, 1300 Wavre, Belgium.
authors.forename: G C
authors.initials: GC
authors.lastname: Meier
authors.affiliation: Department of Applied Mathematics, University of Waterloo, 200 University Avenue West, Waterloo, ON, Canada N2L 3G1; Department of Mathematics & Statistics, University of Guelph, 50 Stone Road East, Guelph, ON, Canada N1G 2W1.
authors.forename: C T
authors.initials: CT
authors.lastname: Bauch
mesh_terms: D006801:Humans; D017589:Immunization Programs; D053118:Influenza A Virus, H1N1 Subtype; D053122:Influenza A Virus, H3N2 Subtype; D009981:Influenza B virus; D007252:Influenza Vaccines / Q000627:therapeutic use*; D007251:Influenza, Human / Q000517:prevention & control*; D008962:Models, Theoretical; D009864:Ontario
chemical_list: D007252:Influenza Vaccines
keywords: Canada; Dynamic transmission model; Influenza; Ontario; TIV; Universal vaccination