INFLUENZA RESPONSE ACTIVITIES Year-round seasonal influenza activities provide the foundation for any influenza pandemic response. Surveillance and monitoring, research and development, delivery of MCMs (for example, vaccines and therapeutics, diagnostics, and respiratory protective devices) and non-pharmaceutical interventions (NPIs), health care system response, and communications are integral to the domains and objectives described in detail later in this Update. Public health preparedness work on seasonal influenza continues throughout the year because influenza viruses circle the globe in a constant state of updates to the vaccine formulation s annual evolution and emergence that necessitate for both the Northern and Southern Hemispheres. Detecting unpredictable outbreaks of novel influenza viruses with human pandemic potential might prompt a sudden change in this mode of operation, which must be addressed by accelerating and amplifying this work specifically with the new virus. It also affects incident response activities, which prioritize and coordinate public health efforts to address a potential pandemic, sometimes even as the seasonal influenza efforts must continue. Shortly after a novel influenza virus has been detected and transmitted among humans, HHS will have determined if vaccines in the NPIVS are likely to offer protection, begun to develop a safe and effective vaccine against the novel influenza virus, determined its susceptibility to antiviral drugs, and triggered a series of domestic and international response activities to mitigate the potential risk of further spread of the virus. A comprehensive U.S. government (USG)-coordinated pandemic response will consider an array of non- pharmaceutical and pharmaceutical intervention options to mitigate pandemic impact on public health. Despite uncertainty in future pandemic influenza scenarios, developing and implementing a set of planning principles and parameters encompassing a range of potential pandemic impacts will be critical to ensure a prompt and flexible response. Therefore, HHS has developed a process to assess various risk scenarios that estimate illness, outpatient medical care, hospitalizations, intensive care unit care, and deaths for low, moderate, high, and very high severity pandemics. Appendix A contains more information about pandemic influenza scenarios and planning assumptions. 11