Questions and answers about Nobivac™ Lyme

• Why is Nobivac™ Lyme considered a new-generation Lyme vaccine?

• Nobivac™ Lyme is unique in this vaccine category. It is the first Lyme vaccine specifically designed to trigger high levels of borreliacidal antibodies against two Borrelia burgdorferi antigens—outer surface protein A (OspA) and OspC. The vaccine derives this ability to provide dual protection by combining two distinct isolates of B. burgdorferi—one traditional isolate that induces borreliacidal antibodies to OspA; and a second, unique isolate that induces high levels of OspC  borreliacidal antibodies.¹B. burgdorferi express OspA while in the tick’s midgut. After an infected tick attaches to a dog, the expression of OspC is increased as the tick begins taking a bloodmeal.² This increased OspC expression continues throughout the early stages of mammalian infection.3  Therefore, OspC borreliacidal antibodies can provide enhanced protection both by targeting spirochetes in the tick midgut that escape killing by OspA borreliacidal antibodies, and by eliminating OspC-expressing spirochetes in the tick’s salivary glands or in the dog.¹
  

• Why is borreliacidal action against OspC so important?

• A borreliacidal antibody is a type of highly protective antibody that binds to specific outer surface proteins of B. burgdorferi and kills the organism. Some Lyme vaccines induce non-borreliacidal antibodies that bind to Borrelia antigens, but do not kill B. burgdorferi. The most effective protection comes from borreliacidal antibodies that kill B. burgdorferi. OspC is a critical factor in Lyme disease transmission.³ Borreliacidal antibodies against OspA are only effective while B. burgdorferi are expressing OspA in the tick’s midgut. Once the Borrelia have switched to OspC expression—and have escaped to the tick’s salivary glands (or into the dog)—they can only be killed by borreliacidal antibodies to OspC.
  

• How was the borreliacidal activity of Nobivac™ Lyme determined?
• A well established borreliacidal assay was used to measure and verify the antibody response generated by Nobivac™ Lyme against OspA and OspC.⁴ Borreliacidal activity cannot be measured using traditional ELISA analysis.

• How well studied is new Nobivac™ Lyme?
• Despite its recent introduction, Nobivac™ Lyme has already been the subject of four efficacy studies and one field safety trial. One of the efficacy studies has recently been published in the highly respected, peer-reviewed journal, Clinical and Vaccine Immunology,¹ and additional publications are in preparation.

• How safe is new Nobivac™ Lyme?
• Nobivac™ Lyme was found to be safe and well tolerated in a clinical field trial involving more than 600 dogs of various breeds and a wide range of ages (6 weeks to 11 years).⁵ Upon subcutaneous administration, the vaccine was 99.3% reaction-free.⁵ 

• How will the efficacy demonstrated by Nobivac™ Lyme in clinical trials translate in the field?

• As this vaccine has just been licensed, data addressing field efficacy are currently not available; however, studies conducted for USDA approval have demonstrated that Nobivac™ Lyme is 100% efficacious. Future studies will collect field efficacy data.

• Why is Nobivac™ Lyme labeled as an aid in the prevention of subclinical arthritis caused by B. burgdorferi?
• Canine clinical arthritis due to Lyme disease occurs relatively late in the course of illness. Nobivac™ Lyme was shown in clinical trials to prevent the development of arthritis. However, in addition to assessing the effects of the vaccine on arthritic signs such as limping and lameness, investigators conducted histopathology studies to look for the subclinical joint inflammation that ultimately leads to clinical arthritis. The label is therefore worded differently than that for other Lyme vaccines.