Immunity under the skin: potential application for topical delivery of vaccines.

With the technological advances in biomedical sciences and the better understanding of how the immune system works, new immunisation strategies and vaccine delivery options, such sprays, patches, and edible formulations have been developed. This has opened up the possibility of administering vaccines without the use of needles and syringes. Already topical immunisation is a reality and it has the potential to make vaccine delivery more equitable, safer, and efficient. Furthermore, it would increase the rate of vaccine compliance and greatly facilitate the successful implementation of worldwide mass vaccination campaigns against infectious diseases. This review gives a brief account of the latest developments of application of candidate vaccine antigens onto bare skin and describes some of our recent observations using peptide and glycoconjugate vaccines as immunogens.