OspA vaccine

An OspA vaccine is a vaccine designed to prevent Lyme disease by targeting the outer surface protein A (OspA) of *Borrelia burgdorferi* (and other pathogenic *Borrelia* species). The unique mechanism of action of OspA-based vaccines is transmission-blocking: when a tick feeds on a vaccinated host (human, dog, or reservoir rodent), it ingests host antibodies against OspA. These antibodies bind to the OspA protein on the surface of the spirochetes inside the tick's midgut, neutralizing the bacteria and preventing their migration to the salivary glands, thereby blocking transmission to the host. OspA vaccines have been developed for humans (such as the historical LYMErix and the clinical-stage VLA15/PF-07307405), dogs (such as Recombitek Lyme), and wildlife reservoirs (such as the oral bait vaccine LymeShield).

Other names

OspA-based vaccineouter surface protein A vaccine