“On June 18, 1981, the U.S. government announced the creation of the world's first genetically engineered vaccine.
Foot and mouth disease (also called "hoof and mouth" disease) affects livestock -- mostly cattle, sheep, pigs and goats. Sores and weakness are the main symptoms of the disease and, while it is usually not fatal to the animals, the attempts to contain it have historically wrought havoc on international trade, tourism and the world meat industry.
The disease is spread by a virus, and many early vaccines used dead samples of the virus to inoculate animals. However, those early vaccines sometimes caused real outbreaks. In the 1970s, scientists discovered that a vaccine could be made using only a single key protein from the virus. In 1981, genetic engineering was used to produce vast quantities of the protein: by grafting some genetic material from the virus onto laboratory bacteria, the scientists tricked the bacteria into producing only that protein. A vaccine consisting of the protein alone cannot cause the disease.”
http://www.tecsoc.org/pubs/history/2001/jun18.htm
also, lots of good Genetic Engineering material here: http://en.wikipedia.org/wiki/Genetic_engineering