Lyme disease, caused by the bite of Borrelia burgdorferi-infect Ixodes ticks, affects close to half a million Americans each year and can cause serious, long term, chronic health issues such as Lyme arthritis, Lyme encephalopathy, or skin disorders. No human vaccine is currently available and the contractor proposes to develop a novel subunit Lyme disease vaccine adjuvanted with a combination adjuvant composed of two synthetic TLR agonists (TLR4 and TLR7/8).