Abstract: A process for the preparation of a vaccine from substantially viable spirochetal bacteria of Borrelia, preferably Borrelia burgdorferi having immunogenic or therapeutic properties and capable of inducing an immune or therapeutic response against Lyme Disease when administered to a patient is described. The product for use against Lyme Disease is produced by ultrasound treatment of substantially viable spirochetal bacteria of Borrelia burgdorferi. The invention produces a product and a method of treatment that can be used for the immunization and/or therapy of a patient against Lyme Disease to minimize or prevent the contraction of the disease or to treat the disease.