A systematic and regulated approach to the nonclinical safety assessment of vaccines is a relatively recent phenomenon compared to small molecule drugs even though the first vaccine was developed in the 1700s. Due to the discovery of the potential for enhanced disease after vaccination, the switch away from live-attenuated vaccines to new vaccine platforms and technologies, and a better understanding of the immune system, an increased emphasis on the nonclinical evaluation of vaccines has emerged over the past several decades. This webinar will provide a brief history of vaccination including a discussion of critical events in the history of vaccines, the importance of the immune system and vaccination, the concept of herd immunity, and the typical study designs and considerations for the nonclinical assessment of vaccine safety.