Vaccines are administered into a muscle because its a highly vascularized tissue. This means there’s a lot of blood vessels that supply muscle. Therefore, the vaccine can become detected by the immune cells in your blood and your body can initiate the immune process. You want to avoid administration into fat tissue because it is not as vascularized, leading to delayed absorption and possible denaturing (or breakdown) of the vaccine. The deltoid muscle of your arm is a great spot because it often has only a thin layer of fat and a thicker layer of muscle. This site has also been shown as a safe route because of the relatively lower risk in puncturing a major nerve. If you were to inject into something like a foot, you run the risk of missing a muscle and/or puncturing a nerve.
osomocosoRN t1_j4yzpom wrote
Reply to Is there any difference in efficacy when a vaccine is administered somewhere other than the upper arm (e.g. on the foot)? by MercurioLeCher
Vaccines are administered into a muscle because its a highly vascularized tissue. This means there’s a lot of blood vessels that supply muscle. Therefore, the vaccine can become detected by the immune cells in your blood and your body can initiate the immune process. You want to avoid administration into fat tissue because it is not as vascularized, leading to delayed absorption and possible denaturing (or breakdown) of the vaccine. The deltoid muscle of your arm is a great spot because it often has only a thin layer of fat and a thicker layer of muscle. This site has also been shown as a safe route because of the relatively lower risk in puncturing a major nerve. If you were to inject into something like a foot, you run the risk of missing a muscle and/or puncturing a nerve.