You've just got to love the way the first vaccine research was conducted. In 1796, English physician Edward Jenner noticed that dairy workers who caught cowpox (a mild disease) did not get smallpox (a deadly, virulent disease). So Jenner took material from a cowpox sore and scratched it into the arm of a healthy, 8-year-old boy. After said boy came down with cowpox, Jenner then scratched material from a smallpox sore into the child's arm. To presumably everyone's great relief (especially the boy's), the youngster remained healthy and did not develop smallpox. (Obviously, the risk of malpractice suits was not much of an issue in 18th Century England.)

These days, research protocols are a little more sophisticated and complicated, although the basic premise for testing a vaccine is pretty much the same: The researcher vaccinates the animal against the infection or disease using some sort of disease component originally isolated from affected animals and, by one means or another, determines whether the vaccine is safe and effective.

Comes an Idea

The interest in developing a new vaccine often arises, says Yu-Wei Chiang, MS, PhD, senior director of Global Bio R&D at Fort Dodge Animal Health, when there is a need for vaccination as a measure to prevent or reduce the severity of an infection or disease. Recent examples include the emergence of West Nile virus (WNV), equine protozoal myeloencephalitis (EPM), and Potomac horse fever (PHF)