Careful preparation before giving an immunization is very important, and includes selection of the correct syringes and needles.

Syringe selection

A separate syringe should be used for each injection. BCG vaccine should be injected using a 0.1 ml syringe; for all other EPI vaccines, use a 1 ml syringe. Disposable syringes are supplied in sterile plastic packages and are designed to be used once only and then put into a safety box. The safest type recommended by the World Health Organization is the auto-disable (AD) syringe. This has the needle already attached and a plunger mechanism that prevents the syringe from being used a second time. If the syringe and needle are supplied separately, when you remove a syringe from its package, take care not to touch the syringe adapter shown below.

Auto-disable 1 ml syringes, supplied with needles already attached. (Photo: Basiro Davey)

Needle selection

The needle used should be of the appropriate diameter for the vaccine. Typically, vaccines are not very thick liquids, and therefore a fine needle size of 22–26 gauge (outer diameter) can be used. A new needle and syringe is used for each injection. Note that for vaccines that need to be reconstituted with diluent before use, you should use a separate ‘mixing’ syringe and needle (like those shown in Figure 4.4) for reconstitution. Use a new auto-disable (AD) syringe and needle to inject the client.

Parts of a syringe and a hollow needle, showing the areas that should not be touched. (Source: Adapted from WHO, 2004, Immunization in Practice, Module 4, Ensuring Safe Injections, Figures 4-B and 4-C)

The image above shows the parts of a needle — none of which should be touched. Open the protective wrapping around the needle and remove it without touching the adaptor. The needle is inside a plastic outer case. Holding the needle by the outer case, push the needle adapter onto the syringe adapter until they ‘lock’ together firmly.

Last modified: Saturday, 12 July 2014, 5:10 PM