Flu shots have typically been administered intramuscularly for decades in people of all ages. However modern immunological research has shown that delivering the vaccine intramuscularly is a far more invasive method and more than 90% of the vaccine is lost in the muscle and fatty matter under the skin and less than 10% is actually responsible for interacting with the immune system and conferring memory against seasonal flu.
Several pharmaceutical manufacturers such as Sanofi Aventis in collaboration with leading vaccine research labs around the world have demonstrated that flu shots if given intra-dermally, which means right under the skin, instead of deep inside muscle is a much more efficient way to confer the same degree of immunity as the muscle injections.
It has been known that epidermis and dermis, the two layers of skin are extremely rich in immune cells such as dendritic cells which are crucial for harnessing the power of the flu shot. As a result a needle only 1/10th the length of regular intramuscular needle is needed for intradermal injection, making this procedure much safer, less invasive and more friendly to kids as well as adults.
The intradermal injection goes only 1.5 mm deep inside the skin versus 15 to 20 mm deep for the intramuscular injection. The dose volume required for conferring immunity is at least 1/5th that of intramuscular injection. Intramuscular flu shots typically come in 0.5 ml volume, whereas intradermal injection sold under the brand name Fluzone in Europe comes in a compact 0.1 ml volume.
Intradermal injections also require only 1/5th to 1/10th of the dosage administered via intramuscular route. Americans should strongly appeal to State and Federal representatives to bring intradermal flu shots to US market.
