Regulatory Considerations in Vaccine Design

Abstract

Vaccines, both those now approved and those that are in development, represent a variety of technologies, as shown in Table I. Earlier vaccines were preparations of killed, or inactivated, bacterial cells or viruses. Other early vaccines were preparations of bacterial toxoids. Often, it was not known why a vaccine worked, it was only known that it did. As knowledge of disease, immunology, and protection increased, vaccines became more sophisticated. Advances in technology led to vaccines that consisted of purified bacterial or viral antigens, and to live, attenuated viral vaccines. Conjugate technology allows a poorly immunogenic antigen to be coupled to a highly immunogenic carrier molecule. Recombinant technology allows an isolated antigen to be produced without the involvement of the pathogenic organism. Examples of approved vaccines and vaccines in development that illustrate the various technologies used to produce today’s vaccines are also shown in Table I.