Most vaccines available for use in Australia are administered via intramuscular or subcutaneous route, with several being administered intradermally or orally. Administering vaccines via the recommended route and using correct technique is of paramount importance to ensure optimal immune response, minimise side effects and reduce the risk of injury to the patient.

Routes of administration

  • Intramuscular

    Intramuscular vaccines are administered into the muscle layer of tissue at a 90° angle. Muscle contains a vast amount of blood vessels resulting in increased blood supply which enables the vaccine to disperse easily. In addition, muscles contain dendritic (antigen-presenting) immune cells that initiate a long-lasting immune response. Intramuscular vaccines tend to have fewer side-effects other than redness and pain at the injection site, which are usually mild and short lived.

  • Subcutaneous

    Subcutaneous vaccines are administered into the subcutaneous, or fatty layer beneath the skin at a 45° angle. Vaccines designed for subcutaneous administration are absorbed at a slower and more constant rate as there is less blood supply in subcutaneous tissue than muscle.

  • Intradermal

    Intradermal vaccines are administered into the outer layers of skin, between the epidermis and the dermis at a 5-15° angle. The epidermal and dermal layers contain many different cells including the antigen-presenting cells (APC’s) that are thought to play a significant role in mediating an efficient and protective immune response to specific vaccines. The 3 main APC’s are macrophages, dendritic cells and B cells. APC’s present specific antigens to particular cells in the immune system that are responsible in eliciting an immune mediated response that in turn creates memory cells and antibodies.

    Intradermal vaccination is a unique method of vaccine delivery which requires specific training to ensure vaccine safety and efficacy.

  • Oral

    Oral vaccines activate immune cells in the mucousal membranes lining the gastrointestinal tract which is beneficial in protecting against diseases that affect the gut.

    Depending on the vaccine, oral vaccines can come in either tablet or liquid formulation. Liquid vaccines recommended for oral administration should never be injected. Oral vaccines available in tablet form should not be chewed or broken.

    Please note, if an infant receiving an oral vaccine spits out a small amount of the dose of vaccine it is still considered a valid dose and doesn’t need repeating. If they spit out most of the dose of vaccine within minutes of receiving it, a repeat dose should be administered at the same visit.

Injectable vaccines

Intramuscular and subcutaneous injection

  • Recommended site for injection in infants < 12 months of age

    The recommended injection site is the middle third of the vastus lateralis (anterolateral thigh).

    To locate the correct anatomical site for injection:

    • ensure the infant’s leg is completely exposed
    • locate the upper and lower anatomical landmarks- greater trochanter of femur and patella
    • draw an imaginary line between the 2 landmarks down the front of the thigh
    • then imagine the thigh is divided into thirds
    • the correct injection site is located in the middle third and on the outer aspect of the imaginary line (see images below).

    Where only two vaccines are scheduled it is recommended to give one vaccine into each thigh. If more than two vaccines are recommended at the one visit, two vaccines may be given into each thigh ensuring they are separated by 2.5 cm.

    Do not inject into the anterior aspect of the thigh as underlying structures may be damaged.

    In some circumstances (eg; congenital limb malformations, active eczema or hip brace placement) alternate sites should be considered. In these scenarios, alternate sites include the deltoid or opposite anterolateral thigh (ensuring that each vaccine has a 2.5cm spacing).

  • Recommended site for injection in children ≥ 12 months of age, adolescents and adults

    The recommended injection site is the deltoid (upper arm).

    To locate the correct anatomical site for injection:

    • expose the arm completely from the top of the shoulder to the elbow; remove shirt or clothing if needed
    • locate the upper and lower anatomical landmarks- acromion (shoulder tip) and the muscle insertion of the deltoid (deltoid tuberosity)
    • draw an imaginary inverted triangle below the shoulder tip, using the identified landmarks (see images below)
    • the site for injection is halfway between the acromion and the deltoid tuberosity, in the middle of the deltoid muscle (triangle).

    More than one vaccine can be given into the deltoid muscle ensuring each vaccine is separated by 2.5cm.

    For children at 12 and 18 months of age the anterolateral aspect of the thigh may be used as an alternate site when giving more than 2 vaccines [see resources].

Intradermal injection

  • Recommended sites for intradermal injection in any age

    The recommended sites for intradermal administration are the volar (inner) surface of the mid-forearm or over the deltoid region over where the deltoid muscle inserts into the humerus.

    The deltoid region on the left arm is specifically recommended for BCG administration in any age groups as administration at this site minimises the risk of keloid scarring.

  • Which vaccines can be given intradermally?

    Examples of vaccines given by the ID route include BCG and hepatitis B (for non-responders). Mantoux and Q Fever tests are also performed intradermally.

    Hepatitis B vaccine is usually given by the IM route however there is a small percentage of the population who do not mount a protective immune response to the IM course of hepatitis B vaccines. If they have been deemed by their provider as a non-responder the intradermal route is considered as an alternative [refer to MVEC: Hepatitis B for more information].

    §This is the recommended site to minimise the risk of keloid formation
    ¥Refer to MVEC: Hepatitis B for more information on the management of non-responders

  • Intradermal vaccination technique

    • Use a short (10mm) 26-27 gauge needle with a short bevel and a 1ml insulin syringe
    • Wear protective eye wear when administering BCG vaccine as eye splashes can ulcerate
    • Identify the correct injection site (see Table 1 above)
    • Stretch the skin between a finger and your thumb
    • Insert the bevel into the dermis with the bevel facing upwards, to a distance of approx. 2mm. The bevel should be visible through the epidermis

    You should feel resistance as you inject, if you don’t, the needle may be in subcutaneous tissue. If the injection is not intradermal, withdraw the needle and repeat at a new site. When given correctly, an intradermal injection should raise a blanched bleb.

Preparing the site for injection

The skin at the injection site should be visibly clean prior to administering a vaccine. The swabbing of clean skin before giving an injection is not necessary. If the skin is visibly dirty, clean the site with alcohol wash/single use alcohol swab and allow the site to dry completely before administering the injection. If active/infected eczema is present at the recommended site, consider an alternate site to minimise the risk of injection site abscess. If there is no alternate site suitable, consider cleaning the site with an alcohol based wash/single use alcohol swab and allowing the site to dry completely before injecting.

Recommended needle size, length and angle for administering vaccines

* Table adapted from the Australian Immunisation Handbook

Positioning for vaccination

  • Infants and younger children

    It is important that children remain still during a vaccination to ensure that the vaccine can be administered into the correct anatomical site, as well as reduce the risk of any unintended injury (eg. needle stick injury). It is important to involve both the child and parent/guardian in discussions when deciding if a child can sit independently or requires support. When positioning a child for vaccination it is important to ensure that they are comfortable and the mobile joints of the limb receiving the vaccine are stable. The immunisation provider must be able to adequately visualise the anatomical landmarks and correct site for injection (deltoid or anterolateral thigh).

    Infants can be held in the cuddle position or on their parents lap facing the provider, with the parent/guardian holding their arms securely and their thighs completely exposed. Younger children can be held in the cuddle or straddle positions with their upper arm completely exposed as demonstrated in the clip below.

    For infants receiving oral vaccines, it is recommended they are positioned in such a way that the vaccine can be administered via gentle squeezing of the vaccine tube into their inner cheek, such as a feeding position.

  • Older children, adolescents and adults

    It is recommended that older children, adolescents and adults sit in a straight-backed chair with their feet on the floor for vaccine administration. Providers should encourage the vaccine recipient to relax their forearms and rest their hands on their upper thighs, keeping their arms flexed at the elbow to assist in relaxing the deltoid muscle.

    Vaccine recipients who are prone to vasovagal responses (fainting) should be vaccinated lying down to prevent unintended injury due to a fall.

Authors: Mel Addison (SAEFVIC Research Nurse, Murdoch Children’s Research Institute) and Rachael McGuire (SAEFVIC Research Nurse, Murdoch Children’s Research Institute)

Reviewed by: Francesca Machingaifa (MVEC Education Nurse Coordinator) and Rachael McGuire (MVEC Education Nurse Coordinator)

Date: December 15, 2022

Materials in this section are updated as new information and vaccines become available. The Melbourne Vaccine Education Centre (MVEC) staff regularly reviews materials for accuracy.

You should not consider the information in this site to be specific, professional medical advice for your personal health or for your family’s personal health. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult a healthcare professional.