Mantoux technique injection requires specialized training by clinical personnel. Microneedle systems and patch-based delivery (accompanied by skin permeabilization technologies) offer the promise of simplified vaccination methods that require minimal training and may permit self-vaccination by patients in certain scenarios. This not only benefits routine vaccination scenarios, but is especially important to mass vaccination campaigns associated with disease eradication programs or pandemic emergencies. In contrast, some of the novel ID delivery methods, such as projectile delivery and tattoo guns, introduce new, sophisticated devices that require additional training of clinical personnel. Assuming the injection is done properly, the Mantoux technique can administer essentially all of the vaccine into the skin. Hollow microneedles and projectile delivery can be similarly efficient. However, solid microneedles typically retain some vaccine on the device and patch-based skin permeabilization methods are extremely inefficient, such that most vaccine typically remains on the skin surface. The efficiency of vaccine utilization will be of critical importance for new, costly vaccines, as well as in developing countries where vaccine cost can be a significant barrier to access.