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Principal investigator:
John Parmer
University of Georgia
Email: parmer@uga.edu
Homepage: http://chrc.uga.edu/people/students.html
Sample size: 599
Field period: 4/25/2011-8/11/2011
2) Are there significant differences in cooperation with smallpox vaccine recommendations based on experimental groups (trust vs. confidence)? 3) Does trust in CDC influence smallpox risk perceptions? 4) Does knowledge of smallpox influence the relationship between trust and risk perceptions? Study participants will then read short messages describing a smallpox outbreak scenario, the role of CDC in such an event, and vaccine information and recommendations for members of a community believed to have been exposed to the virus. Message content will be structured to contain information that enhances one of the two pathways to cooperation as described by the TCC Model. One message condition will aim to enhance trust by highlighting the shared values dimension of trust. A second message condition will aim to enhance confidence in the CDC to effectively manage the smallpox outbreak by highlighting past performance during recent public health crises (i.e. anthrax and SARS) as well as approaches that were successfully employed in the past to control smallpox outbreaks. After reading one of two messages, participants will then complete surveys measuring shared values with CDC, past performance of CDC, confidence in CDC to manage smallpox, smallpox risk perceptions, knowledge of smallpox, and behavioral intention to cooperate with government vaccine recommendations. Covariates will include general confidence, general trust, and demographics. If 250 respondents are randomized to each condition, this will provide at least 86% power at the two-sided alpha=0.05 significance level to detect a difference of 0.14 between the proportions cooperating with smallpox vaccine recommendations (e.g., 57% versus 43%). With 200 respondents per group, the power is 87% to detect a difference of 0.16 between cooperation proportions. Risk perception measures are adapted from previous research on influenza vaccination and risk perceptions (Weinstein et al., 2007) and include measures of risk magnitude, perceived severity, and concern. Confidence in the risk management institution (CDC) will be measured by a 3-item scale measuring institutional confidence as judgments of competence and expertise. Items measuring general trust and general confidence were selected from the literature with acceptable internal consistencies, 0.67 and 0.54 respectively (Siegrist, Gutscher, & Earle, 2005). Finally, a measure of participant's general knowledge of the CDC will be administered before exposure to message conditions and included as a covariate. Past performance and confidence factors did not appear as significant predictors in this study. It may be that respondents have insufficient experience or knowledge of how DHS has managed past crises for these constructs to influence their willingness to cooperate. Consistent with the literature, risk perceptions were strongly predictive of cooperation with protective measures. Risk perception is a central construct in many theories of health behavior that suggest the risk a person perceives from a health threat will be associated with their willingness to engage in behaviors to protect them from that threat. In the case of vaccine acceptance, it would be interesting to examine the influence of risk perceptions of the vaccine, in addition to those associated with the disease. Future studies on trust and vaccine behavior should measure risk perceptions of both the hazard and vaccine to assess the influence of vaccine risk perceptions on cooperation, independent of risk perceptions related to the hazard.
Two of the six constructs outlined by Trust, Confidence and Cooperation model were found to be significant positive predictors of cooperation with official smallpox vaccine recommendations. General trust, a personality trait rather than a measure of trust in a specific entity, was found to be an important predictor of cooperation. Similar values were found to be a significant predictor of cooperation as well, whereas shared values were not. However, the confidence intervals for the odds ratios of shared values (0.921-1.238) and similar values (1.013-1.420) overlap and therefore these findings remain tentative. That general trust and similar values, and not shared values (tentatively), predict cooperation is an interesting finding. The distinction between similar values and shared values is unclear in the literature. The results of this study suggest that these two constructs are indeed distinct from one another, but that only similar values may influence cooperation during a smallpox outbreak.