Today, vaccines are a recurring topic since many countries are administering covid vaccines on a daily basis. As you probably already know, one of the most effective ways to administer medications is intravenously.
Each syringe and needle has its own characteristics and it’s important to know which one is needed for each occasion. Syringes are not only used for vaccines, they can also be used for blood collection or transfusions.
Vaccines contain antigens that cause the body’s immune system to produce antibodies that can protect it against the targeted disease. This is known as the immune response.
Antigens are modified or partial forms of the disease-causing virus, bacteria or toxin that the vaccine protects against. Because the antigen is altered from its original form, it cannot cause disease, but it will produce an immune response.
Vaccines can be injected with needles of different lengths and thicknesses. The gauge of the needle refers to the thickness. The higher the specification number, the finer the needle. For example, a 25 G needle is approximately 0.5 mm in diameter, which is thinner than a 23 G needle with a 0.6 mm diameter.
Syringes are composed of the following parts:
The syringe has a round tube that contains the liquid (either medicine, blood or serum). This tube is calibrated, it can be chosen depending on the use that is going to be given and can range from 0.5 ml to 60 ml.
A 1 to 3 ml syringe is usually sufficient for subcutaneous or under the skin injections, or intramuscular or under the muscle injections. Larger syringes are more common for intravenous injections of medication or for irrigating wounds.
There are different types of injections: intravenous, intradermal, intramuscular, and subcutaneous injections. Intradermal and subcutaneous injections usually have a smaller hole and shorter needles. These types of injections are generally used for insulin, PPD skin tests, and more.
Intravenous injection is used to inject drugs through a vein into a vein so that these substances go directly into the blood. Intramuscular injections must reach the muscles and require longer needles. The thickness depends on the drug to be injected, since the dose can vary depending on the diagnosis.
“G” stands for “Gauge” and is the inside diameter of the pointer. It’s measured by comparing the flow that can pass through a needle of known gauge. Typically, the 18G pink needle is used in emergency situations and the 27G gray needle is used in treatment. This is because the rose is larger and the fluid passes faster.
These are the different needle sizes and colors:
Depending on the dose of vaccine to be administered, it’s recommended to use a 1 ml or 3 ml syringe and depending on where the vaccine will be administered, it’s very important to choose the correct needle size to make sure that you optimize the immune response and reduce the risk of any type of injection site reaction.
The adjuvant vaccines should be injected into the muscles, rather than the subcutaneous tissues, thereby preventing inflammation and the formation of granulomas. In addition, care must be taken because if the vaccine is accidentally injected into the lymphatic circulation, the absorption of the vaccine may be impaired.
First, it’s important to verify that all the necessary material is available in order to administer the vaccine:
You must also verify that the available or necessary vaccines are in their containers and with their original labels. Then, they must be removed from the refrigerator approximately 10 minutes before administration so that the temperature is not too cold to avoid pain when injecting.
Next, make sure that the vaccine corresponds to the vaccine to be administered and check the expiration date. If you’re unfamiliar with the vaccine, you should review the SmPC and check the recommended route of administration.
If it’s a vaccine to be reconstituted, you should do it with a loading needle. In pre-filled vaccines, it’s only necessary to attach the appropriate biosafety needle and shake. Finally, the vaccine should be shaken and its condition inspected in order to verify that there are no precipitates or suspended particles.
The route to be used is determined by immunogenicity and reactogenicity. In the Technical Data Sheet, you can find the recommendation of the vaccine manufacturer.
First, you must choose the anatomical place according to the route and age of the person to be vaccinated.
Deltoids or external aspect of the upper third of the arm (triceps). The thigh could also be used, in children under 12 months.
Here are the steps to administer a vaccine:
After the vaccine has been administered, there are few steps to follow in order to guarantee that everything works out fine:
It’s also recommended that the patient remain for approximately 30 minutes in the waiting room for observation. This is to detect possible immediate adverse reactions
Parenteral vaccines should be injected where immunogenicity is high and the risk of local damage to blood vessels, nerves, or tissues is low. For this, the needle must be selected with the appropriate size and length.
The type of needle depends on the route, the anatomical site and the chosen administration technique. The age and muscle mass of the person to be vaccinated must also be taken into account.
The most common needles to administer vaccines are: