expected to substantially shorten timelines to make vaccines available to immunize the U.S. population. Whereas vaccines are the most effective MCMs to reduce the overall public health impact of influenza pandemics, other MCMs are critically important to mitigate emerging pandemics before effective vaccines become available. Such other measures are an essential part of a comprehensive mitigation response at different stages of the pandemic to protect diverse at-risk populations. These countermeasures include antiviral drugs and other therapeutics, diagnostic tests to determine whether someone has been infected with influenza (and the influenza subtype) or has a secondary bacterial infection, personal protective equipment (including respiratory protective ices, face shields, gowns, and gloves) to protect those in direct contact with infected dev individuals, and mechanical ventilators to provide respiratory support to those who are severely ill. Global surveillance to determine the susceptibility of influenza viruses to licensed and approved antiviral drugs is conducted to inform clinical guidance for treatment. Because influenza viruses change constantly, they can become resistant to one or more of the antiviral drugs used to treat or prevent influenza. A pandemic caused by drug-resistant viruses would pose an unprecedented challenge to the public health system. Development of new, broad-spectrum therapeutics with different mechanisms of action from currently approved antiviral drugs, as well as host-targeted therapeutic approaches, may mitigate the emergence of antiviral drug resistance that could rapidly reduce the effectiveness of single drug approaches. HHS has made significant strides in developing, manufacturing, and distributing influenza MCMs, and in monitoring their use, safety, and effectiveness. Notable progress over the past decade and key actions for the next 10 years include the following: • Developing and clearing a diagnostic test that can identify an influenza subtype in 20 minutes. • Developing and licensing new cell-based, recombinant, and adjuvanted vaccines for seasonal and pandemic influenza. • Evolving and diversifying vaccine production processes from solely egg-based technology to cell- and recombinant-based vaccines, increasing domestic seasonal influenza vaccine production capacity that can be leveraged for pandemic response. The number of manufacturers that can supply vaccine to the United States has expanded from two in the 2004–2005 influenza season to six in the 2016–2017 season. • Expanding the pre-pandemic vaccine stockpile subtype diversity comprising monovalent bulk product from subtype A(H5N1) representing various antigenically distinct H5 viruses from different clades, as well as bulks from the most recent subtype A(H7N9). • Establishing AS03 and MF-59 adjuvant stockpiles to permit antigen-sparing approaches, thus increasing the number of people who can be vaccinated with adjuvanted vaccine. 23