Hundreds of millions have rolled up their sleeves for the COVID-19 vaccine, but why haven’t they rolled up their pants instead? What’s he science behind why we get most vaccines in our arm?
Most vaccines are given in the muscle—this is known as an intramuscular injection (肌肉注射). Some vaccines, are given orally. Others are given just beneath the skin.
But why is he muscle so important, and does location matter?
Muscles make an excellent vaccine administration (药物的施用) site because muscle tissue contains important immune cells Thee immune cells recognize the antigen, a tiny piece of a virus or bacteria introduced by the vaccine that stimulates an immune response. In the case of the COVID-19 vaccine the immune cells in the muscle tissue pick up these antigens(抗原) and present therm to the lymph nodes(淋巴结). Injecting the vaccine into muscle tissue keeps the vaccine localized, allowing immune cells to sound the alarm to other immune cells and get to work. Once a vaccine is recognized by the immune cells in the muscle, these cells carry the antigen to lymph vessels, which transport the antigen-carrying immune cells into the lymph nodes. Lymph nodes, important parts of our immune system, contain more immune cells that recognize the antigens in vaccines and start the immune process of creating antibodies.
Muscle tissue also tends to keep vaccine reactions localized. Injecting a vaccine into the deltoid (三角肌) muscle may result in local inflammation(红肿) or soreness at the injection site. If certain vaccines are injected into fat issue, the chance of irritation (刺激) and inflammation reaction increases because fat tissue has poor blood supply, leading to poor absorption of some vaccine components.
Yet another deciding factor in vaccine administration location is the size of the muscle. Adults and children aged three and older tend to receive vaccines in their upper arm in the deltoid. Younger children receive their vaccines mid-thigh(大腿) because their arm muscles are smaller and less developed.
Another consideration during vaccine administration is convenience and patient acceptability. Can you imagine taking down your pants at a clinic with strangers around? Rolling up your sleeve is much easier and more preferred.
8. How many reasons are mentioned for the vaccines given in the muscle?
9. According to the passage, for most people, ______is the preferred vaccination site.
A.the lymph nodes | B.the mouth |
C.the arm | D.the thigh |
10. What does the underlined expression “pick up” in the fourth paragraph probably ______ mean?
A.recognize | B.gather |
C.clean up | D.come down with |
11. What may be the best title for the passage?
A.Don’t be afraid of injection |
B.why we get shots in the arm |
C.An interesting secret to injection |
D.How vaccines are given into the muscle |