The objective of the contract is to identify novel adjuvants, as part of the NIAID Vaccine Adjuvant Discovery Program and the contractor has developed a portfolio of novel compounds. As part of HHS’ effort to advance the development of vaccines against tick-borne pathogens, the contractor will conduct a formal comparison of adjuvants for a vaccine against severe fever with thrombocytopenia syndrome virus (SFTSV). No such vaccine is currently available, and the contractor has a model system in which the efficacy of such vaccines can be evaluated. SFTS was first reported in 2009 and has since been spreading. It has a fatality rate in humans, an accidental host, of up to 30% and is transmitted not only by ticks, but can also be spread from person to person. In this project, beta-propiolactone-inactivated virus will be formulated with three experimental adjuvants (in comparison to Alum and Addavax) and the efficacy of the vaccines will be evaluated.