Lyme disease is a bacterial infection caused by Borrelia Burgdorferi that is transmitted to humans through the bite of blacklegged ticks. It is also anecdotally said to be transmitted by the wood tick. However, it can be difficult to diagnose  because the symptoms mimic many other illnesses, and many people may not show any signs of infection until months or even years after being bitten.

The development of the Lyme vaccine began in the early 1990s with a race between two companies, SmithKline Beecham and Pasteur Mérieux Connaught. Both companies focused on the most common outer surface protein, OspA, as a target for their vaccine.