title: Human mobility and the spatial transmission of influenza in the United States.
abstract: Seasonal influenza epidemics offer unique opportunities to study the invasion and re-invasion waves of a pathogen in a partially immune population. Detailed patterns of spread remain elusive, however, due to lack of granular disease data. Here we model high-volume city-level medical claims data and human mobility proxies to explore the drivers of influenza spread in the US during 2002-2010. Although the speed and pathways of spread varied across seasons, seven of eight epidemics likely originated in the Southern US. Each epidemic was associated with 1-5 early long-range transmission events, half of which sparked onward transmission. Gravity model estimates indicate a sharp decay in influenza transmission with the distance between infectious and susceptible cities, consistent with spread dominated by work commutes rather than air traffic. Two early-onset seasons associated with antigenic novelty had particularly localized modes of spread, suggesting that novel strains may spread in a more localized fashion than previously anticipated.
authors.affiliation: Fogarty International Center, National Institutes of Health, Bethesda, MD, United States of America.|Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States of America.
authors.forename: Vivek
authors.initials: V
authors.lastname: Charu
authors.affiliation: Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States of America.
authors.forename: Scott
authors.initials: S
authors.lastname: Zeger
authors.affiliation: Fogarty International Center, National Institutes of Health, Bethesda, MD, United States of America.|Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Julia
authors.initials: J
authors.lastname: Gog
authors.affiliation: Fogarty International Center, National Institutes of Health, Bethesda, MD, United States of America.|Department of Entomology, Pennsylvania State University, State College, Pennsylvania, United States of America.
authors.forename: Ottar N
authors.initials: ON
authors.lastname: Bjørnstad
authors.affiliation: Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Stephen
authors.identifier: 0000-0001-6000-8387
authors.initials: S
authors.lastname: Kissler
authors.affiliation: Fogarty International Center, National Institutes of Health, Bethesda, MD, United States of America.|Department of Public Health, Copenhagen University, Copenhagen, Denmark.
authors.forename: Lone
authors.initials: L
authors.lastname: Simonsen
authors.affiliation: Fogarty International Center, National Institutes of Health, Bethesda, MD, United States of America.|Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, United States of America.
authors.forename: Bryan T
authors.initials: BT
authors.lastname: Grenfell
authors.affiliation: Fogarty International Center, National Institutes of Health, Bethesda, MD, United States of America.
authors.forename: Cécile
authors.initials: C
authors.lastname: Viboud
mesh_terms: D003198:Computer Simulation; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D063426:Human Migration / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D007251:Influenza, Human / Q000453:epidemiology* / Q000635:transmission*; D015233:Models, Statistical; D016016:Proportional Hazards Models; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D062211:Spatio-Temporal Analysis; D014186:Transportation / Q000706:statistics & numerical data*; D014195:Travel / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology; D014505:Urban Population / Q000706:statistics & numerical data*