Introductory Chapter: Immunization - Vaccine Adjuvant Delivery System and Strategies

Immunization plays a key role in maintaining human health as it saves millions of lives in the most economical way from lethal pathogens and other fatal diseases each year, thanks to the advanced development of model vaccines, which are biological preparations containing an antigenic agent that resembles a disease-causing microorganism to stimulate the host’s immune system, thus providing active acquired immunity to a particular disease and destroying it [1, 2]. Since Jenner’s pioneering inoculations in the late eighteenth century, vaccines have been successfully developed to combat various diseases and each year saved numerous lives from, mostly, lethal infections and now also certain cancers [3, 4]. Especially, taking advantage of the tools discovered in microbiology and immunology, vaccines have recently obtained great achievements as demonstrated by their successful performances in conquering some formidable pathogens, such as smallpox and rabies, which are used to claim many lives. However, the list of pathogens for which there exist no vaccines is still long, and, in particular, many pathogens, such as human immunodeficiency virus (HIV), herpes simplex virus (HSV), and Ebola virus (EBV), are still posing a big threat to human life, therefore needing urgently the effective products to cope with their infections [5].