Teses / dissertações: "Immunisation"

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Leask, J. "Understanding Immunisation Controversies". Thesis, The University of Sydney, 2002. http://hdl.handle.net/2123/12503.

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Resumo:

BACKGROUND: Mass childhood vaccination has had a profound impact on reducing morbidity and mortality from a number of infectious diseases. Ironically, as vaccine preventable diseases become less common and so less visible to the public, greater attention is afforded to vaccine risks. In the UK, Japan, France and the USA, controversies about the safety of vaccines have led to declining public confidence in the practice which, at times, has lowered immunisation rates, leading to disease outbreaks and deaths. Public health workers are often perplexed at how to respond in such situations. In order to plan effective communication strategies it is necessary to understand how controversies about vaccine safety escalate. This thesis describes the nature of public controversies about vaccine safety by examining the discourses of the anti-vaccination lobby, the mass media, parents and health professionals. THE ANTI-VACCINATION MOVEMENT: This thesis first explores the activities of the anti-vaccination movement and their efforts to disseminate their core messages to the wider public. In Australia, the anti-vaccination lobby are a largely unseen force in sustaining controversies about vaccine safety. This small but vocal movement are well organised and strategic. A description of their activities in Australia demonstrates the comprehensiveness of their efforts to oppose vaccination at the political, community and mass media level. THE NEWS MEDIA: The news media have the potential to influence public perceptions about childhood vaccination. To complement previous research on the nature of anti-vaccination reportage, this thesis examines positive coverage from four and a half years of newsprint articles about immunisation published in Australian newspapers. Located at the core of anti-vaccination discourse is an appeal to an individualistic ideology that upholds vigilance against the erosion of civil liberties, suspicion of authority figures and the back-to-nature idyll. By contrast, pro-vaccination rhetoric is centred on notions of threat from personified and malevolent infectious disease and vaccines as saviours and modern medical miracles. PARENTS AND VACCINE SAFETY: Focus groups with new mothers explore how they deconstruct competing messages about vaccine safety, using vignettes from broadcast media. Results suggest that anti-vaccination claims are most potent when they come from medical sources and/or include stories and images of allegedly vaccine-damaged children. Mothers apply complex assessments of risk and benefit in their decision-making and draw on analogies to explain their position. Trust in vaccine providers, personal experiences with vaccine preventable diseases, the advice of family and friends, and scepticism about the media as a source of information are important in decision making. Implicit in attempts to counter negative publicity are assumptions that factual information about disease and vaccines will alone reassure parents. However, when their support for vaccination is challenged, mothers are more likely to mobilise images of children with vaccine preventable diseases than numerical assessments of risk and benefit. More generally, parental support of vaccination is sustained by recourse to normative beliefs and the desire to follow convention. Parents also have an underlying desire to actively protect their children from diseases that are dreaded. VACCINATION PROVIDERS: Their encounter with vaccine providers is fundamental to parental decision making and negotiation of conflicting messages about vaccination. An interview study with doctors incorporating simulated scenarios explores how doctors address parental concerns about vaccination in the clinical encounter. In this study, doctors acknowledge a mother’s concerns, tailor their discussion to the individual circumstance of the mother and convey the notion of choice. They attempt to compare vaccine and disease risks using mainly qualitative estimates of disease and adverse event incidence. Possibly less helpful aspects of the encounters are when doctors became adversarial, discredit a mother’s source of information, ask hypothetical “how would you feel if…” questions, over-use scientific language, enter into games of scientific ping pong or give bland “you’re wrong” statements. Doctors face difficulty when communicating with patients whose paradigms are diametrically opposed to their own. Influencing these encounters is their underlying relationship with the patient, messages from the mass media and theories that help guide the doctor’s communication efforts. THE MODEL: This thesis proposes a model for how vaccine controversies can lead to sustained declines in vaccination rates. This is achieved through highlighting the above perspectives and examining the current controversy over the combined measles, mumps, rubella vaccine and it’s unsupported link to autism. It suggests that vaccine safety concerns ‘catch fire’ when the source of a controversy is trusted, seen as expert and coming from a prestigious body or publication. Greater potency is gained when vaccines are implicated as the cause of a dreaded condition and when the link has some biological plausibility face value. Moving personal testimony about allegedly vaccine-damaged children can eclipse official attempts to provide factual reassurances which, by comparison, appear bland and uncompelling. Finally, a less acknowledged but possibly more important factor is the erosion of confidence among health professionals and confusion at the level of service delivery where upstream changes can have exponential effects.