National and international policies to mitigate disease threats.

To devise and implement effective health policy, we must define the problem, choose the tools, craft the policy, build consensus, set goals and deadlines, raise funds and take action. Success or failure depends on the perception of risk, the strength of the underlying science, the efficacy of the technology, ownership and intellectual property, the conflict between individual and public health, the choice of weaker (guidelines) and stronger (law) policy instruments, the level of public interest, political opportunity, institutional inertia, mechanisms for enforcement and who foots the bill. All these things considered, this paper is a brief policy-making guide by example, illustrating some achievements and disappointments with reference to cholera, drug-resistant tuberculosis, HIV/AIDS and rabies.