health action. The rationale of the smallpox vaccination program was never adequately explained to key constituencies and communication with CDC was constrained by unknown factors. As a result, the public health and health care communities seemed unable to trust the government and CDC fully when they called for smallpox vaccination in large numbers and at a rapid pace. The pace of vaccination ultimately declined, and the number of vaccinees reached fell far short of initial expectations. CDC’s credibility has been recognized to be an important asset.

The role of CDC as the nation’s public health leader—providing scientific and public health reasoning to inform the process of policy-making and to explain the rationale for policy to key constituencies—must be safeguarded. The reality and perception of CDC’s independence to communicate openly and transparently came into question during the implementation of the smallpox vaccination program. It is essential to preserve the public health and health care communities’ trust in CDC’s leadership; therefore, when reasons of national security limit CDC’s ability to perform its role, that fact should be made explicit and public.

The trust of the general public in government and government’s ability to protect the public’s health also is a critical requirement for responding to bioterrorism (and other public health threats). Communication experts (Covello and Sandman, 2001; Sandman, 2002) and a recent survey (Lasker, 2004) have shown that people’s trust in the government must be handled with great care, but it is an essential requirement for effective communication; people are less likely to panic and more likely to participate constructively during an emergency if they believe they can trust government agencies to provide accurate and timely information.

The public’s confidence in the public health system’s capacity to protect people in a bioterrorism event efficiently and effectively depends on evidence and reassurance that CDC and the nation’s public health agencies are prepared. Although considerable resources and effort have been invested in the smallpox vaccination program, it remains unclear whether the nation is more prepared than it was before to respond to an attack with smallpox virus; preparedness has not been defined, clear goals have not been set, and there has been no comprehensive and systematic assessment of smallpox preparedness. Such an assessment is necessary to demonstrate that the nation is prepared and to communicate that to the public.

Since the eighteenth century, American governments at all levels have determined that public health is an appropriate concern. The history of the agencies established shows regular debates about the array of activities to be expected and the degree to which decision makers and the public agree with the rationale that prompts action. Decisions about regulation of drinking water, protection of the food chain, immunization of children, and many other matters reflect those concerns. Without a regular exchange of