New technology for improved vaccine safety and efficacy.

Nearly all of the 2000 vaccines presently licensed by the US Department of Agriculture for veterinary use in the United States are conventional vaccines containing either killed or modified live whole bacteria or viruses. Recent advances in molecular biology, immunology, microbiology, and genetics and in understanding microbial pathogenesis have led to the development of a wide variety of new approaches for developing safer and more effective vaccines. This article briefly describes these new technologies and their potential advantages and disadvantages as compared with conventional killed and modified live vaccines.