Novel human vaccine strategies and the 5th Framework Programme: pushing the envelope

Mucosal vaccines could result in a great scientific and practical achievement. More than three decades of research in experimental models have shown promising results in stimulating mucosal immune responses, thus, it was expected that within a short time mucosal vaccines for human use could be achieved. Indeed this is not being the case. In the last few years, the most important oral vaccine, the anti-polio developed by Sabin in the fifties, has been progressively abandoned in developed countries to avoid the few cases of disease caused by the vaccine. Furthermore, two recently developed mucosal vaccines for human use against rotavirus diarrhoea and influenza were withdrawn after a short period in the market because of adverse reactions among the vaccinees. This controversial situation has created a difficult future for research on mucosal vaccine at the industrial level. A great help and encouragement for believers in mucosal vaccines has been given by the EU Commission through the 5th Framework Programme (5FP). At the end of the first projects of the 5FP, it is quite clear that mucosal vaccines are experiencing a real renaissance. The Euroconference/Workshop "Novel Strategies of Mucosal Immunisation through Exploitation of Mechanisms of Innate Immunity in Pathogen-Host Interaction", organised under the sponsorship of the EU Commission and reported in this special issue of Vaccine, witnesses a very creative moment of European groups involved in mucosal immunology. This conclusive paper of the issue is intended to describe a positive experience of some European scientists that have been working together in organised fashion within two EU projects. The first, defined by the acronym MUCIMM, was aimed to pave the way to tackle mucosal vaccines with different approaches, mainly that of new delivery systems and adjuvants, that of dissecting the fine mechanisms of basic mucosal responses and that of obtaining meaningful assays to measure human immune responses to mucosal vaccines. The second, the MUCADJ project, was aimed to prove that an intranasally delivered influenza vaccine induces protective levels of immunity in human adult volunteers. The results obtained demonstrate that mucosal vaccines for humans are feasible. It is interesting to note how this model of making biomedical research is flourishing, becoming an example for work organisation. At the same time it is important to underline some of the limits of this cooperative approach and it is also mandatory to spend a word of consciousness regarding the impact that the new European regulations could exert on mucosal vaccines, particularly for those based on live delivery systems. In a world where the damages caused by syringe needles are still largely visible, mucosal vaccines could represent an extremely important tool to fight infections, particularly in the large population of the most impoverished. The EU Commission will still encourage and support mucosal vaccines in the 6FP. The scientific community must decide in which direction has to proceed to avoid regulatory problems that could halt a promising tool to improve human health. The envelope has been pushed, the trip begins.