Date Published: December 3, 2009
Publisher: Public Library of Science
Author(s): James Holland Jones, Marcel Salathé, Erik von Elm. http://doi.org/10.1371/journal.pone.0008032
Abstract: Since late April, 2009, a novel influenza virus A (H1N1), generally referred to as the “swine flu,” has spread around the globe and infected hundreds of thousands of people. During the first few days after the initial outbreak in Mexico, extensive media coverage together with a high degree of uncertainty about the transmissibility and mortality rate associated with the virus caused widespread concern in the population. The spread of an infectious disease can be strongly influenced by behavioral changes (e.g., social distancing) during the early phase of an epidemic, but data on risk perception and behavioral response to a novel virus is usually collected with a substantial delay or after an epidemic has run its course.
Partial Text: An ongoing outbreak of novel influenza A(H1N1), colloquially referred to as “swine flu,” has caused over 200,000 confirmed cases (as of 28 August 2009 ). Because of under-reporting, the actual number of people infected is substantially larger, particularly considering that many countries have ceased testing for A(H1N1) . As human-to-human transmission became widespread in at least one region of the world, WHO rapidly declared the outbreak an imminent pandemic  and with widespread human infection, WHO declared a phase 6 pandemic on 11 June 2009, where it remains at the time of submission . The virus appears to have a higher reproduction number and somewhat higher case fatality ratio than recent seasonal influenza viruses , , and has certainly caused great concern in the population, fueled by both extensive media coverage and an initially high level of uncertainty about mortality rates and transmissibility of the virus.
We begin by presenting descriptive results of the survey and follow with our primary analytical questions from the survey, namely, testing the hypothesis that respondents’ affective state mediates their protective action.
Our results indicate that respondents’ behavior varies systematically with covariates from demographic, epidemiological, media, and affective domains. People’s anxiety about swine flu and the preventative actions they took to avoid infection declined as the perceived gravity of the novel outbreak waned. Overall, subjective risk perception was low and people’s belief in their ability to avoid infection was high. Both of these distributions nonetheless showed a marked bimodality, with a large proportion of respondents indicating a higher subjective risk and more protective actions taken than the majority (Figures 3–4).