title: Exploring cross-protection between influenza strains by an epidemiological model.
abstract: Almost all influenza surveillance systems of temperate countries report a single influenza illness peak each winter. Although several strains of different types or subtypes may co-circulate, they exceptionally lead to two distinct illness peaks during the same winter. We hypothesize that cross-protection between the different strains can, by itself, explain this absence of succeeding illness peaks. We used a dynamic population model to describe the spread of two influenza strains during one season. Cross-protection is included through a parameter defined as the reduction of host risk of infection to one strain after infection with another strain. Different scenarios are performed with two strains emerging with different time-lags, for different levels of cross-protection. We show that a cross-protection of 50% between the two strains is sufficient to explain why we observe a single influenza illness peak in temperate countries.
authors.affiliation: Institut National de la Santé Et de la Recherche Médicale INSERM Unité 444, Faculté de Médecine Saint-Antoine, 27 rue Chaligny, 75571 Paris Cedex 12, France. alevenu@dgf.uchile.cl
authors.forename: Audrey
authors.initials: A
authors.lastname: Lavenu
authors.forename: Alain-Jacques
authors.initials: AJ
authors.lastname: Valleron
authors.forename: Fabrice
authors.initials: F
authors.lastname: Carrat
mesh_terms: D004196:Disease Outbreaks; D006801:Humans; D015994:Incidence; D007251:Influenza, Human / Q000453:epidemiology* / Q000276:immunology* / Q000821:virology; D008954:Models, Biological; D009975:Orthomyxoviridae / Q000145:classification* / Q000472:pathogenicity