Urbanization and Humidity Shape the Intensity of Influenza Epidemics in U.S. Cities

Overview

Journal Science

Specialty Science

Date 2018 Oct 6

PMID 30287659

Citations 137

Authors

Benjamin D Dalziel

Stephen Kissler

Julia R Gog

Cecile Viboud

Ottar N Bjornstad

C Jessica E Metcalf

Bryan T Grenfell

Affiliations

Soon will be listed here.

Abstract

Influenza epidemics vary in intensity from year to year, driven by climatic conditions and by viral antigenic evolution. However, important spatial variation remains unexplained. Here we show predictable differences in influenza incidence among cities, driven by population size and structure. Weekly incidence data from 603 cities in the United States reveal that epidemics in smaller cities are focused on shorter periods of the influenza season, whereas in larger cities, incidence is more diffuse. Base transmission potential estimated from city-level incidence data is positively correlated with population size and with spatiotemporal organization in population density, indicating a milder response to climate forcing in metropolises. This suggests that urban centers incubate critical chains of transmission outside of peak climatic conditions, altering the spatiotemporal geometry of herd immunity.

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