May 25, 2021 16:00:00

Why is the new coronavirus vaccine given by intramuscular injection?

The new coronavirus vaccination has started in Japan, but when vaccinated, a method called

'intramuscular injection' is used instead of the 'subcutaneous injection' used for influenza vaccines. Libby Richards, an associate professor of nursing at Purdue University, explains why the intramuscular injection method is used.

Why do we get shots in the arm? It's all about the muscle
https://theconversation.com/why-do-we-get-shots-in-the-arm-its-all-about-the-muscle-161259

According to Richards, the answer to the question 'Why intramuscular injection?' Is 'because muscle tissue contains important immune cells.' When the vaccine is recognized by immune cells in the muscle, these cells carry the

antigen through the lymph vessels to the lymph nodes. Lymph nodes, an important component of the human immune system, are rich in cells that recognize antigens in vaccines and produce antibodies.

The new coronavirus vaccine is injected into the deltoid muscle in the upper arm, because many lymph nodes are concentrated in the armpit near the deltoid muscle. The reason why some vaccines are injected into the thighs is that the lymph nodes are also concentrated in the groin near the thighs.

Intramuscular injection also has the purpose of minimizing local reactions such as inflammation at the injection site. When injected into the subcutaneous tissue, which has a poor drainage pathway, compared to muscles with abundant blood supply, it is more likely that a local reaction will occur because the injected substance will be retained for a long time.

Yet another reason is that it is 'convenient'. It is much easier and more acceptable to patients to roll up their sleeves than to take off their pants in the hospital, saying, 'For vaccinations that must be done in the shortest possible time, injections into the upper arm are just because the procedure is easier. It's preferred, 'explains Richards.