- II. Provide a taxonomy of control policies and to collate as completely as possible the results of modeling studies that assess their effectiveness in specific or in combination. This allows the comparison of the effectiveness of the same policy when viewed in isolation, or as part of a strategy group of policies aimed at containment or mitigation. This difference is relevant if particular countries may afford only one or few of the policies rather than the most effective group of policies.

- III. Further the debate on the appropriate international mix of funding for pandemic influenza preparedness that reduces the global risk of such an event. As per the current distribution of funding, countries with past outbreaks and at risk of future outbreaks are spending less per capita than some countries with no outbreaks but larger resources. This imbalance in preparedness spending is driven by large pre‐ investments in the latter group in mitigation policies such as vaccine development and antiviral stockpiling. These are resource intensive and hence disproportionately the preserve of wealthier countries. Such spending is driven by a logic summarized as ‘hope for the best but prepare for the worst’. This assumes that containment policies after a pandemic outbreak in the frontline states (those with current or past outbreaks) will fail and hence the spread to the West is inevitable; and further that subsequent containment policies at airports or other entry points in the West will also fail. Discussion of the modeling results below, especially from studies that address a global redistribution of resources<sup>80</sup> , should illuminate this debate.

Ethical and cost considerations can make the choice complex between two similarly effective and feasible control policies. For example, some mitigation policies are selective in terms of who is pre‐protected from infection, raising ethical issues that require review. Cost‐effectiveness studies of policies for pandemic influenza have been rare, reflecting the difficulty in rigorously estimating the benefits or costs, or negotiating the ethical issues in valuing sickness and death. The few such studies available will be reviewed. A different angle is taken by studies that estimate the general benefit of preventive policies in terms of the avoided macroeconomic costs of a potential pandemic. Such studies of potential national and international losses to economic activity are beyond the scope of this review.

Immediately below, a section surveys what is currently known about the properties of a pandemic influenza virus that determine the ease of containment or mitigation in an outbreak. Also in the same section, the results from published reviews of efficacy for a few policies are summarized. The next section provides a broad overview of the major methods for modeling the transmission of pandemic influenza and for the prospective comparison of control policies. The main section of the paper follows, initially providing the taxonomy of interventions. On this basis, studies that compare various control policies – for containment and mitigation – are analyzed, and those that evaluate a specific policy. The penultimate section reviews cost and cost‐effectiveness studies. Ethical issues are briefly discussed in the concluding section, which can be read as an executive summary of the review. The intended audience includes public health practitioners, policymakers, and researchers involved in health. No detailed knowledge of pandemic influenza epidemiology is assumed.

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