Synchrony, Waves, and Spatial Hierarchies in the Spread of Influenza

Viboud, Cécile; Bjørnstad, Ottar N.; Smith, David L.; Simonsen, Lone; Miller, Mark A.; Grenfell, Bryan T.

doi:10.1126/science.1125237

Cited by 785 publications

(978 citation statements)

References 28 publications

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“…A/H1N1 viruses have intermediate evolutionary rate [59] and did not display a clear relationship with transmissibility in our study. Our finding of increased transmissibility of A/H3N2 viruses reinforces a recent study showing more rapid dispersal of A/H3N2 epidemics across the United States, as compared with A/H1N1-B epidemics [18].…”

Section: Discussionsupporting

confidence: 89%

“…Past studies have estimated the reproduction number of individual influenza seasons, in particular for pandemics [11][12][13][14][15][16][17][18][19]. However, no study has yet reported estimates of the reproduction number for several countries and consecutive influenza seasons in the interpandemic period, where a fraction of the population is immune due to previous influenza exposure or vaccination.…”

Section: Introductionmentioning

confidence: 99%

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Seasonal influenza in the United States, France, and Australia: transmission and prospects for control

2007

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SUMMARYRecurrent epidemics of influenza are observed seasonally around the world with considerable health and economic consequences. A key quantity for the control of infectious diseases is the reproduction number, which measures the transmissibility of a pathogen and determines the magnitude of public health interventions necessary to control epidemics. Here we applied a simple epidemic model to weekly indicators of influenza mortality to estimate the reproduction numbers of seasonal influenza epidemics spanning three decades in the United States, France, and Australia. We found similar distributions of reproduction number estimates in the three countries, with mean value 1.3 and important year-to-year variability (range 0.9-2.1). Estimates derived from two different mortality indicators (pneumonia and influenza excess deaths and influenza-specific deaths) were in close agreement for the United States (correlation = 0.61, P < 0.001) and France (correlation = 0.79, P < 0.001), but not Australia. Interestingly, high prevalence of A/H3N2 influenza viruses was associated with high transmission seasons (P = 0.006), while B viruses were more prevalent in low transmission seasons (P = 0.004). The current vaccination strategy targeted at people at highest risk of severe disease outcome is suboptimal because current vaccines are poorly immunogenic in these population groups. Our results suggest that interrupting transmission of seasonal influenza would require a relatively high vaccination coverage (> 60 %) in healthy individuals who respond well to vaccine, in addition to periodic re-vaccination due to evolving viral antigens and waning population immunity.

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Section: Discussionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Seasonal influenza in the United States, France, and Australia: transmission and prospects for control

2007

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“…This suggests that cities with different mobility patterns may also differ in the rate at which their inhabitants have infectious contact, leading to variation among cities in the risk of an epidemic [5][6][7]. Human movement patterns are heterogeneous at a wide range of scales-from within a building [8] to among countries [9][10][11], as evidenced by diverse sources of data, including the movements of mobile phone users [12,13], air travel patterns [9][10][11] and census data on commuting patterns [10,14,15]. At each scale, there appear collective mobility patterns maintained far from those predicted by homogeneous random movement.…”

Section: Introductionmentioning

confidence: 99%

“…Individual variation in rates of infectious contact can significantly alter patterns of disease spread [6,7,15,[19][20][21] and theoretical models of disease dynamics within and among cities (both individual-based simulations [5,7,10,15,[22][23][24] and metapopulation models [10,11,14,15,[25][26][27]) have shown that heterogeneous contact patterns are potentially important in determining urban epidemic dynamics. However, few studies have examined whether empirical variation in intracity mobility patterns is sufficient to drive detectable differences in epidemic dynamics among cities.…”

Section: Introductionmentioning

confidence: 99%

Human mobility patterns predict divergent epidemic dynamics among cities

2013

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The epidemic dynamics of infectious diseases vary among cities, but it is unclear how this is caused by patterns of infectious contact among individuals. Here, we ask whether systematic differences in human mobility patterns are sufficient to cause inter-city variation in epidemic dynamics for infectious diseases spread by casual contact between hosts. We analyse census data on the mobility patterns of every full-time worker in 48 Canadian cities, finding a power-law relationship between population size and the level of organization in mobility patterns, where in larger cities, a greater fraction of workers travel to work in a few focal locations. Similarly sized cities also vary in the level of organization in their mobility patterns, equivalent on average to the variation expected from a 2.64-fold change in population size. Systematic variation in mobility patterns is sufficient to cause significant differences among cities in infectious disease dynamics—even among cities of the same size—according to an individual-based model of airborne pathogen transmission parametrized with the mobility data. This suggests that differences among cities in host contact patterns are sufficient to drive differences in infectious disease dynamics and provides a framework for testing the effects of host mobility patterns in city-level disease data.

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“…Commuting destinations for both workers and students are randomly assigned by employing a gravity model (Viboud et al, 2006), integrated with specific data (ISTAT, 2001b).…”

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confidence: 99%

An individual-based model of hepatitis A transmission

Ajelli

Merler

2009

Journal of Theoretical Biology

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Viral hepatitis A, as other endemic diseases, represents a public health priority worldwide. To study long-time scale human pathogens through individual-based simulations requires the development of a dynamic network of contacts. In this work, we introduce an individual-based model accounting for the birth and death of the individuals, the generation of new households, and the educational career of the individuals, in order to investigate viral hepatitis A dynamics in the most affected Italian areas. Intervention options such as targeted vaccination, social distancing measures (e.g. closure of day care centers and kindergartens) and improvements in standards of living and hygiene are evaluated. Results show that a very low vaccination coverage is sufficient to control hepatitis A in Italy, while its elimination is not possible since new cases are continuously imported from high endemicity areas outside the country. Finally, the considered social distancing measures can be counterproductive since the fraction of recovered individuals does not decline while the age at infection increases, thus augmenting the probability of developing acute symptoms. Preprint submitted to Elsevier 31 March 2009A c c e p t e d m a n u s c r i p t

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Synchrony, Waves, and Spatial Hierarchies in the Spread of Influenza

Cited by 785 publications

References 28 publications

Seasonal influenza in the United States, France, and Australia: transmission and prospects for control

Seasonal influenza in the United States, France, and Australia: transmission and prospects for control

Human mobility patterns predict divergent epidemic dynamics among cities

An individual-based model of hepatitis A transmission

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