Mucosal surfaces are the major point-of-entry for most pathogens. Establishing a first line of defence within the mucosal epithelium would therefore prevent the infection from establishing itself in the host. Furthermore, needle-free immunization also shows socio-economical advantages such as increasing patient compliance, decreasing the cost by removing manufacturing steps (e.g., the sterilisation necessary for injectable forms) and, in some cases, avoiding cold storage conditions, which represents an issue especially in developing countries. The present work on mucosal immunization will focus on non-replicative virus-like particles (VLP) and virosomes, which are non-replicative reconstituted virus lacking from the viral genetic material. They appear as a safe alternative to live, attenuated and inactivated vaccines.