The ID vaccine uses a smaller needle, and requires a smaller pathogen load to be introduced into the body in order to achieve the same effect. Typical vaccine needles go through the skin, then a layer of fat, and finally enter the muscle. Intradermal vaccines are injected into the skin through a small, ultra-thin needle. Because the skin has more immune cells than the muscle, an intradermal vaccine is able to use the skin's natural defenses, providing a similar level of protection as the traditional flu shot.
The ID vaccine is only available for patients over 18 years old and is recommended for those taking anti-coagulation medication