Prevention of an infectious disease is preferable to the need for treatment of the disease. The concept of immunomodulating the host response, by the administration of a vaccine, to subsequently induce protective immunity against an infectious agent, has proven to be a successful strategy in many instances. The success of the polio and smallpox vaccines to eradicate disease has saved a countless number of lives and healthcare dollars over the last 60 years or more. Furthermore, prevention of childhood diseases such as rubella, mumps, and pertussis, as well as the more recent vaccines to protect against some pneumococcal infections, has been extremely beneficial. Obviously, prevention of other infectious diseases through a protective vaccine would also be beneficial.