What's going on with vaccination?
Photo source: Hubin central health center of Boxing County
Let's talk about the new coronal vaccine that we are currently using. According to international standards, the new coronal vaccine will also be injected intramuscularly. The method of administration is intramuscular injection of the needle at right angles into the deltoid muscle on the lateral side of the upper arm (this is also the way of administration of most vaccines at present).
There must be a reason why the muscle area stands out as an excellent vaccination site.
First of all, muscle has a good blood supply, which can help spread the vaccine (in contrast, the blood supply of adipose tissue is much worse); There is also an important immune cell (dendritic cell) in the muscle tissue, which can recognize the antigen components in the vaccine and start the body's immune response; In addition, muscle tissue can also limit the composition of the vaccine to a certain range, prolong the stay time of the vaccine, and activate the immune system to the maximum extent. If the vaccine is injected directly into the blood, the composition of the vaccine will be easily removed by other non-specific immune cells, and it may be difficult to play a role.
Moreover, there are abundant blood vessels in the muscle, which can more quickly transport the vaccine ingredients injected into the muscle to the whole body. If intramuscular injection causes inflammation, it is only local inflammation, or only sore at the inoculation site.
Of course, deltoid is not the only muscle that meets these two conditions. For infants or young children, the thigh is the preferred position when they need to receive more than two injections on a single limb, because the muscles here are larger, they can receive multiple injections, and they are not far from the inguinal lymph nodes. But for older people, it's obviously easier to inject deltoid muscle (it's easier to roll up sleeves than take off pants, of course).
Most vaccines choose intramuscular injection, which is also related to the use of adjuvants in vaccines. Adjuvants can enhance the specific immune response of the body to antigens, but may also lead to inflammatory reactions. Muscle can help to control the adverse reactions in a smaller range, with a higher safety factor.
Common vaccines, such as hepatitis B vaccine, hepatitis A inactivated vaccine, influenza vaccine, rabies vaccine, are intramuscular injection. Subcutaneous injection of vaccine is relatively less, mainly measles vaccine, Japanese encephalitis vaccine, etc; Fewer vaccines are injected intradermally, typically BCG (mainly to prevent tuberculous meningitis in children).
Do all vaccines have to be given by injection? In fact, it's not. There are several ways of vaccine administration, such as oral administration.
The existence of sugar pill tells us that good medicine may not be bitter. See watermark for the source of the picture
However, oral vaccines are mostly attenuated vaccines, which are less safe than inactivated vaccines. They are mainly suitable for diseases infected through digestive tract (such as rotavirus vaccine, cholera vaccine, etc.), and their immune effect on diseases infected by other ways is not ideal, so they have not become the main way of vaccine administration.
Of course, oral vaccines also have many advantages. For example, oral administration has no risk of blood pollution, and as an oral drug, it can be made into solid, which is not only more stable, but also conducive to transportation and storage. Therefore, in recent years, research on oral drugs has begun to increase.
In addition to oral vaccine, we know more about inhalation atomization vaccine recently, right?
Image source network
This way of administration requires a smaller dose of vaccine, and it can stimulate mucosal immunity and relieve the pain of injection. No wonder everyone is very concerned about the progress of research and development. It may be the first time that many people have heard of this kind of vaccine for inhalation administration, but in fact, China has approved a vaccine similar to the way of administration, that is, live attenuated nasal spray influenza vaccine.
Photo source Xiaoxiang famous doctor this vaccine through nasal spray to simulate the process of virus infection of the human body, can stimulate the mucosa to produce specific antibodies, and painless, noninvasive, mother no longer have to worry about my fear of injections.
For us and most mammals, that's what immunity is all about. However, for birds, another interesting way of immunity is eye drops.
The chicken is so good. See the watermark for the source of the picture
The hardy gland is located in the back of the eyeball of birds. It is distributed with T cells and B cells. It can produce immune response after vaccination by eye drops. Therefore, birds can be immunized by eye drops.
All of the above immunization methods do not require injection, which is a good news for people who are dizzy and afraid of pain.
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Link to the original text:Tadpole staff