• The epidemiology of the virus (e.g., pathogenicity, mode(s) of transmission, incubation period, the attack rate in different age groups, period of communicability, susceptibility to antivirals)
• The pandemic phase and the amount of virus activity in the area (for example, after the pandemic is declared, the focus will be on community measures designed to reduce the risk of influenza—e.g. public education, restricting public gatherings)
• The characteristics of the community (i.e., some measures, such as school closures, are more effective in rural than in urban areas)
• Public acceptance of the measures
• The resources required to implement the measures (i.e., some measures, such as tracing contacts and active surveillance, are labor intensive and may not be an effective use of resources once the virus is widespread in the community.