Medical ethics generally applies to individual interactions between physicians and patients. Conversely, public health ethics typically applies to interactions between an agency or institution and a community or population. Four main principles underlie medical ethics: autonomy, nonmaleficence, beneficence, and justice. By contrast, public health ethical principles address issues such as interdependence, community trust, fundamentality, and justice. In large part because of the significant community-level effects of public health issues, medical ethics are suboptimal for assessing community-level public health interventions or plans-especially in the area of emergency preparedness. To be effective, as well as ethical, public health preparedness efforts must address all of the core principles of public health ethics.