The degree of trust that recipients place in the communicators of information about vaccine risks and benefits, as well as the ability of the communicators to convey any existing uncertainty about adverse events, also influences decisions made about vaccination. For example, the University of Pennsylvania study found that nonvaccinators exhibited significantly more skepticism about medical information in general and about vaccines and their effectiveness in particular (Meszaros et al., 1996).
A lawyer stated that there is a fundamental conflict of interest in vaccine risk communication because health officials and health care providers, in the interest of public health, generally see their roles as encouraging immunization. Their natural tendency, consequently, will be to emphasize the benefits of immunization and in their communications minimize the risks about vaccines. At the same time, they have the responsibility to provide their patients accurate and unbiased information on the nature and extent of the risks involved with vaccination. Ultimately, the public might be better served if public health officials, health care providers, and the population they serve all worked towards the development of a trusting relationship, in which public health officials were seen as having responsibility for ensuring the health of the population, including balancing disease and vaccine risks (IOM, 1996b).
A consumer advocate said that vaccine manufacturers, providers, and policymakers knew that there were risks associated with vaccine use when vaccines were first marketed but did not adequately communicate those risks to the public. Nor was it communicated that there was some uncertainty and disagreement about what was known, she said. "This failure to communicate what medical science does and does not know about vaccine risks was quite simply perceived as a fundamental betrayal of trust by those who were being asked to take the risks," she said. When government and industry's media campaigns to achieve a high vaccination rate downplayed vaccine risks, there was further erosion of trust. Overzealous enforcement of mandatory vaccination laws, she said, also fosters a lack of trust.
A vaccine manufacturer's representative noted that part of the problem with trying to convey risks following vaccinations to the general public is that frequently the true risks are not known. There are a range of views as to which adverse events should be discussed in written statements and other communications about vaccines. The position at one end of the continuum is to describe only those risks that are shown by conventional scientific standards to be causally associated with the vaccine. The position at the other end is to claim safety only with regard to adverse events that can be shown not to be associated with the vaccine and then to describe equally all other putative adverse events. The