Wednesday, September 15, 2010

PloS ONE: Social Network Sensors for Early Detection of Contagious Outbreaks

Nicholas A. Christakis1,2*, James H. Fowler3,4

1 Faculty of Arts & Sciences, Harvard University, Boston, Massachusetts, United States of America, 2 Health Care Policy Department, Harvard Medical School, Boston, Massachusetts, United States of America, 3 School of Medicine, University of California San Diego, La Jolla, California, United States of America, 4 Division of Social Sciences, University of California San Diego, La Jolla, California, United States of America

Abstract

Current methods for the detection of contagious outbreaks give contemporaneous information about the course of an epidemic at best. It is known that individuals near the center of a social network are likely to be infected sooner during the course of an outbreak, on average, than those at the periphery. Unfortunately, mapping a whole network to identify central individuals who might be monitored for infection is typically very difficult. We propose an alternative strategy that does not require ascertainment of global network structure, namely, simply monitoring the friends of randomly selected individuals. Such individuals are known to be more central. To evaluate whether such a friend group could indeed provide early detection, we studied a flu outbreak at Harvard College in late 2009. We followed 744 students who were either members of a group of randomly chosen individuals or a group of their friends. Based on clinical diagnoses, the progression of the epidemic in the friend group occurred 13.9 days (95% C.I. 9.9–16.6) in advance of the randomly chosen group (i.e., the population as a whole). The friend group also showed a significant lead time (p>

Citation: Christakis NA, Fowler JH (2010) Social Network Sensors for Early Detection of Contagious Outbreaks. PLoS ONE 5(9): e12948. doi:10.1371/journal.pone.0012948

Editor: Olaf Sporns, Indiana University, United States of America

Received: June 22, 2010; Accepted: August 13, 2010; Published: September 15, 2010

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