Technical Abstract: Vaccines are important tools for control and elimination of infectious diseases. Research in pursuit of new and improved vaccines for diseases of veterinary significance needs to build on existing data in order to advance in a timely manner despite limited funding and resources. A particularly relevant example of the problem is PRRS in swine. Vaccine research to develop new PRRS vaccines dominates the funding activities of the National Pork Board PRRS Initiative and the USDA PRRS Coordinated Agricultural Project (PRRS-CAP). We, the undersigned, are participants in PRRS-CAP. We recommend that publicly funded research and development of PRRS vaccines incorporate as part of the research plan a set of common elements that will encourage accelerated analysis and evaluation of ideas and technologies, minimize duplication, and facilitate unbiased scientific evaluation and comparison. These are 1) All projects must include a challenge experiment; 2) Challenge experiments must be performed with a virulent strain substantially genetically different from the vaccine strain; 3) The challenge model can be either respiratory disease or reproductive disease or both; and 4) Challenge studies must include for comparison a positive control consisting of an existing, widely used commercial product. Implementation of such requirements would facilitate rapid evaluation of candidate vaccine antigens, delivery technologies, and other immune protection strategies, thus promoting more rapid advancement of methods for the prevention and elimination of PRRS. We also realize that such a strategy would be of value for other animal diseases in which vaccine development or improvement is problematic.