Vaccine delivery--current trends and future.

Since its discovery in 1796 by Edward Jenner, vaccines have been an integral aspect of therapeutics, combating a number of infectious diseases with remarkable success. In recent years, due to rapid advances in proteomics, genomics, biotechnology and immunology and the plethora of knowledge amassed in related fields, it is fair to expect vaccine development to progress at an exponential pace. However, as we march on into the 21st century, we are still struggling in our efforts to eradicate fatal diseases such as AIDS, malaria and hepatitis C due, in part, to the absence of effective vaccines against these diseases. Vaccine development faces major challenges both technologically and economically. Newer vaccines that are stable, economical, require fewer doses and can be administered using needle free systems are a worldwide priority. An ideal theoretical vaccine may not be cogent unless formulated and delivered aptly. Delivery of vaccines via oral, intranasal, transcutaneous and intradermal routes will decrease the risk of needle-borne diseases and may eliminate the need for trained personnel and sterile equipment. Crucial to the success of a vaccine is the delivery strategy that is to be employed. Currently, various techniques involving DNA vaccines, adjuvants, microparticles and transgenic plants are being developed and evaluated. Although, no major breakthrough is in prospect, these systems have potential and will take immunization to a new technological level. This review will focus on the current development of some novel vaccine delivery systems and will explore the non-parenteral routes of vaccine administration.