The greatest and most rapid changes in health occurred during the last century, primarily attributed to a higher standard of living, improved public health measures, and the application of science-based medicine. In addition to clean water, sanitation, and the use of antibiotics, vaccines are an essential part of these public health achievements. Vaccine research and development as well as the implementation of effective vaccine delivery programs has led to the eradication and elimination of several once-common serious infectious diseases. Discovery begins with the recognition of an infectious disease burden and the opportunity to prevent it through immunization. Basic scientific research brings ideas forward into the product development pathway toward the ultimate goal of translating these ideas into safe and effective medical products. Safety and efficacy testing are conducted at every step of this product development pathway. Both basic and targeted research is the basis for the development of vaccine candidates and new vaccine platforms that offer greater flexibility in vaccine development and production. New tools, such as efficient antigen identification techniques, coupled with a profoundly greater understanding of the immune response are available to define basic mechanisms of disease to support design and development of novel and improved vaccines. Determining “proof of concept” regarding immunogenicity and safety follows – initially in preclinical studies in animals and then in humans to further evaluate safety and efficacy. Finally, researchers conduct scientific characterization of the vaccine and the process for producing it, including scaling the manufacturing process to commercial levels before vaccines are moved into human testing. Vaccines are developed through public-private partnerships – including researchers, government, manufacturers, purchasers, and policy makers – who have been successful at bringing new vaccines to licensure for broad use. These partnerships are central to the success of vaccine innovations. Through targeted investments in science and technology, such partnerships have led to the development of hundreds of vaccine candidates at various stages of maturity in the development pipeline. The Global HIV Enterprise is an example of unprecedented collaboration among organizations worldwide, including the National Institutes of Health (NIH), the International AIDS Vaccine Initiative, USAID, the Bill and Melinda Gates Foundation, and many others working together to accelerate the development of a preventive HIV vaccine. Because vaccine development is time- and resource-intensive, establishing and understanding priorities for development and encouraging collaboration between stakeholders is essential in addressing the challenges of developing new and improved vaccines. Fostering continued investment from all sectors is critical as technological approaches and disease threats expand amid increasing costs to develop, license, and deliver vaccines. The aim of Goal 1 is to develop new and improved vaccines and to address the upstream research and development aspects of vaccines for domestic and global health priorities. The research needs of other aspects of the vaccine enterprise (e.g., program implementation, distribution logistics, communication) are included within other goals in the Plan. Objectives Prioritize new vaccine targets of domestic and global public health importance. Support research to develop and manufacture new vaccine candidates and improve current vaccines to prevent infectious diseases. Support research on novel and improved vaccine delivery methods. Increase understanding of the host immune system. Support product development, evaluation, and production techniques of vaccine candidates and the scientific tools needed for their evaluation. Improve the tools, standards, and approaches to assess the safety, efficacy, and quality of vaccines. For more information on this goal and the defined set of strategies for achieving each objective mentioned above, view the National Vaccine Plan.