Evidence-based immunization in horses

Evidence of vaccine efficacy is essential for practitioners when giving advice to clients about the relative merits of different vaccines or when trying to evaluate the economic benefits of instituting a vaccine program. In equine veterinary medicine, this sort of data, which are necessary to make informed decisions about vaccine use and effectiveness, are often not available. Veterinarians need to consider the epidemiology of the disease in question, the type of vaccine that they are administering to the animal, the immunologic constraints of the vaccine technology, and the available evidence of efficacy when they are evaluating which vaccine to use or whether to vaccinate at all.