Essential epidemiological mechanisms underpinning the transmission dynamics of seasonal influenza.

TitleEssential epidemiological mechanisms underpinning the transmission dynamics of seasonal influenza.
Publication TypeJournal Article
Year of Publication2012
AuthorsTruscott J, Fraser C, Cauchemez S, Meeyai A, Hinsley W, Donnelly CA, Ghani A, Ferguson N
JournalJ R Soc Interface
Date Published2012 Feb 7
KeywordsAge Factors, Antigens, Viral, Disease Outbreaks, Humans, Influenza, Human, Models, Immunological, Population Dynamics, Risk Factors, Seasons

Seasonal influenza has considerable impact around the world, both economically and in mortality among risk groups, but there is considerable uncertainty as to the essential mechanisms and their parametrization. In this paper, we identify a number of characteristic features of influenza incidence time series in temperate regions, including ranges of annual attack rates and outbreak durations. By constraining the output of simple models to match these characteristic features, we investigate the role played by population heterogeneity, multiple strains, cross-immunity and the rate of strain evolution in the generation of incidence time series. Results indicate that an age-structured model with non-random mixing and co-circulating strains are both required to match observed time-series data. Our work gives estimates of the seasonal peak basic reproduction number, R(0), in the range 1.6-3. Estimates of R(0) are strongly correlated with the timescale for waning of immunity to current circulating seasonal influenza strain, which we estimate is between 3 and 8 years. Seasonal variation in transmissibility is largely confined to 15-30% of its mean value. While population heterogeneity and cross-immunity are required mechanisms, the degree of heterogeneity and cross-immunity is not tightly constrained. We discuss our findings in the context of other work fitting to seasonal influenza data.

Alternate JournalJ R Soc Interface
PubMed ID21715400
PubMed Central IDPMC3243394
Grant ListG0800596 / / Medical Research Council / United Kingdom
U54 GM088491 / GM / NIGMS NIH HHS / United States
/ / Medical Research Council / United Kingdom
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