This guidance provides information on implementation of section 3086 of the 21st Century Cures Act (Cures Act) (Public Law 114-255), which added section 565A of the Federal Food, Drug, and Cosmetic Act (FD&C Act) (21 U.S.C. 360bbb-4a). Section 565A of the FD&C Act requires FDA to award a priority review voucher (PRV) to sponsors of certain medical countermeasure (MCM) applications that meet the criteria specified in that section. Since the enactment of the Cures Act, the Agency has received inquiries about the scope of section 565A of the FD&C Act, its relation to other PRV programs, and how various aspects of section 565A of the FD&C Act should be interpreted. The purpose of this guidance is to provide responses to those questions.