ABSTRACT
INTRODUCTION Currently, most vaccines are administered parenterally by needle and syringe. However, in industrialized countries, a proportion of children and adults have an aversion to injections. Therefore, administering vaccines without needles would be expected to increase compliance. Indeed, concern among parents about the increasing number of injections that must be given to infants and toddlers to deliver the recommended vaccines has been a strong impetus for the development of infant combination vaccines. The administration of vaccines by needle and syringe also poses occupational safety risks of needle sticks for health care providers. This could emerge as a more substantive issue in the future should it become necessary to immunize large populations expeditiously in response to a bioterror or emerging infection emergency.
