Chapter 11 - Parenteral vaccine delivery: From basic principles to new developments

Abstract

Parenteral administration of vaccines has been a highly effective strategy for preventing and controlling infectious diseases. Parenteral vaccines are administered through routes other than the gastrointestinal tract, such as intramuscular, subcutaneous, or intradermal injections. These routes offer several advantages, including the rapid and efficient delivery of antigens to the immune system, induction of robust immune responses, and enhanced vaccine stability. Moreover, parenteral vaccines can be formulated with adjuvants to further enhance their immunogenicity. Recent advancements in parenteral vaccine development have focused on several key areas. First, there has been significant progress in the design and formulation of novel antigen delivery systems, such as liposomes, virus-like particles, and nanoparticle-based carriers. These systems offer improved antigen stability, controlled release, and targeted delivery to specific immune cells. Second, advances in recombinant DNA technology have enabled the production of highly purified and well-characterized antigens, improving the safety and efficacy of parenteral vaccines. Third, the development of novel adjuvants, including toll-like receptor agonists and nanoparticle-based adjuvants, has facilitated the modulation of immune responses and the induction of long-lasting immunity. However, parenteral vaccine development also faces several challenges. Vaccine formulation and stability are critical factors, as certain antigens may degrade or lose potency during storage and transportation. Additionally, the choice of adjuvants requires careful consideration, as they need to elicit robust immune responses without causing adverse reactions. Furthermore, the high cost and complex manufacturing processes associated with parenteral vaccines can limit their accessibility, particularly in resource-limited settings. This chapter provides an overview of parenteral vaccine development, highlighting recent advancements and addressing the challenges associated with this approach.