Overview of Vaccine Adjuvants: Introduction, History, and Current Status.

Adjuvants are included in sub-unit or recombinant vaccines to enhance the potency of poorly immunogenic antigens. Adjuvant discovery is as complex as it is a multidiscplinary intersection of formulation science, immunology, toxicology, and biology. Adjuvants such as alum, which have been in use for the past 90 years, have illustrated that adjuvant research is a methodical process. As science advances, new analytical tools are developed which allows us to delve deeper into the various mechanisms that generates a potent immune response. Additionally, these new techniques help the field learn about our existing vaccines and what makes them safe, and effective, allowing us to leverage that in the next generation of vaccines. Our goal in this chapter is to define the concept, need, and mechanism of adjuvants in the vaccine field while describing its history, present use, and future prospects. More details on individual adjuvants and their formulation, development, mechanism, and use will be covered in depth in the next chapters.