Health risk communication has traditionally consisted of messages designed to encourage behavior that reduces individual and societal risk (e.g., smoking cessation and seat-belt use). Increasingly, risk communication, including health risk communication, is seen as an interactive process of an exchange of information and opinion among individuals, groups, and institutions (National Research Council, 1989). To be effective, risk communications must address the experiences, beliefs, values, and attitudes of message recipients as well as providers. Understanding how risks are perceived and the inherent biases of both message providers and recipients are key to good risk communication.
Although health risk communication has been an active research area for several decades, the science and practice of vaccine risk communication are not yet well developed. Many of the problems with risk communication in general, however, apply to vaccine risks. In particular, the rarity of vaccine-preventable diseases in the vaccine era makes it more difficult to communicate the risks of these diseases. Recent studies illustrate specific factors influencing how vaccine risks and benefits are perceived by and acted on by consumers and vaccine providers. Individual's immunization decisions are influenced by decisions that others make. People might prefer to do what a majority of others do or may take advantage of the protection afforded by high immunization rates and not be vaccinated; they may also be influenced to vaccinate by the fact that vaccination would protect others. Other factors include perceptions of disease risk and the ability to control those risks, and preferences for the risks of diseases per se over
risks of the vaccine against them. Studies have also addressed issues of mandatory vaccination, informed consent, individual rights versus societal welfare, and people's trust in information providers.
Information on vaccine benefits and risks is currently limited in availability and scope. Information available to consumers today includes the vaccine information statements issued by the Centers for Disease Control and Prevention (CDC), material from other federal agencies such as the Food and Drug Administration (FDA) and National Institutes of Health (NIH), manufacturers' package inserts that accompany vaccines, oral communications from health care providers, and information provided by a variety of nonprofit and consumer organizations.
Three major themes emerged during the workshop. First, risk communication is a dynamic process in which many participate, and these individuals are influenced by a wide range of circumstances, interests, and information needs. Effective risk communication depends on the providers' and recipients' understanding more than simply the risks and benefits; background experiences and values also influence the process (Zeckhauser, 1973). Good risk communication recognizes a diversity of form and context needs in the general population. Both the method and content of risk communication should reflect the goals of the communication, which could include advocacy, education, and development of a decisionmaking partnership (in any combination).
Second, the goal that all parties share regarding vaccine risk communication should be informed decisionmaking. Consent for vaccination is truly ''informed'' when the members of the public know the risks and benefits and make voluntary decisions. The discussion of mandatory vaccination at the workshop suggested that it may interfere with informed consent and may damage trust and deter effective communication, and thus needs to be carefully weighed against its benefits.
Finally, there is often uncertainty about estimates of the risk associated with vaccination. Risk communication is more effective when this uncertainty is stated and when the risks are quantified as much as science permits. Trust is a key component of the exchange of information at every level, and overconfidence about risk estimates that are later shown to be incorrect contributes to a breakdown of trust among public health officials, vaccine manufacturers, and the public. Continued research to improve the understanding of vaccine risks is critical to maximizing mutual understanding and trust.
Workshop participants suggested a number of ways to improve vaccine risk communications, including: tailoring it to audience needs, abilities, and interests; improving the format and structure of printed material; presenting more balanced information; adding references and bibliographies to communications; and providing estimates of the likelihood of risks when known, while stating the