Alternative routes of immunization for prevention of infectious diseases: A new paradigm for the 21st century

The prevention of infectious diseases by the use of vaccines represents one of medicine's greatest triumphs during the 20th century. This era has witn essed the global eradication of smallpox as a result of Jennerian cowpox va ccination, the elimination of paralytic poliomyelitis from the western hemi sphere. and within 5-10 years the anticipated eradication of poliomyelitis worldwide as a result of the poliovirus vaccines. Next slated for worldwide eradication is measles, the great killer of infants and children, which ea ch year extracts a global mortality of one million victims. Throughout the 20th century the percutaneous (i.e., subcutaneous or intramuscular) route h as almost exclusively been the preferred way to administer vaccines. Howeve r, as a result of several important scientific discoveries made during the 20th century, including new tissue-culturing techniques, the development of recombinant DNAA technology, and genetic sequencing, a whole new generatio n of tailor-made modern vaccines has become available, including DNA vaccin es and transgenic plant vaccines. Moreover, it became apparent that alterna tive routes of administration of vaccines, such as by aerosol immunization and transcutaneous skin patches, might be more appropriate and more effecti ve than immunization via the parenteral route. This paper describes some of the recent advances relating to alternative methods of immunization and wi ll focus primarily on the development and use of respiratory aerosolized va ccines.