ID vaccination offers potential immunologic advantages to public health. The skin is known to be a site rich in antigen-presenting cells, some of which are specific to the skin, including epidermal Langerhans cells and dermal dendritic cells (Glenn and Kenney 2006) . In addition, antigen may be taken up directly by lymphatic vessels for transport to antigen-presenting cells in the lymph nodes. At a minimum, the ID route of vaccination appears to follow different pathways to immunity compared to IM or SC routes. However, there is evidence that the ID route is not only different, but is also beneficial (Glenn and Kenney 2006; Lambert and Laurent 2008; Nicolas and Guy 2008) .