Recent years have seen the development of novel technologies that use nanoparticles and microparticles to deliver vaccines by the oral and microneedle-based transdermal route of administration. These new technologies enable the formulation of vaccine particles containing vaccine antigens, without loss of their biological activity during the formulation process. Also, multiple antigens, targeting ligands, and adjuvants can all be encapsulated within the same particle. When administered orally, these particles are designed to withstand the acidic environment of the stomach and are targeted...