V Letter

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

Injectable vaccines

Intramuscular and subcutaneous injection

Intradermal injection

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

Resources

• MVEC: Injection site reactions
• MVEC: Injection site nodules
• MVEC: Shoulder injury related to vaccine administration (SIRVA)
• DHHS: “Where should I inject vaccines?” poster

What is it?

Vaccine-associated enhanced disease (VAED) is a rare phenomenon in which a (usually) more severe clinical presentation of an infection that would normally be seen in an unvaccinated person occurs in someone who has been vaccinated. Antibodies that have been generated from vaccination bind to a pathogen and aide in a virus getting more easily into cells than it would on its own. Vaccines that have been found to cause VAED are no longer in use (see below).

Mechanisms for enhanced disease

VAED has previously been observed during clinical trials involving individuals receiving inactivated whole-virus vaccines against respiratory syncytial virus (RSV). Clinical trials showed that children who had received the vaccine and then were later diagnosed with RSV infection developed more serious RSV symptoms. As a result, this vaccine was never approved for general use.

The other vaccine which has been linked to VAED is one of the earlier versions of the measles vaccines in the 1960s. It was found that following vaccination, children were at higher risk of developing an atypical form of measles disease. This vaccine has since been withdrawn, and the current measles-containing vaccines are not associated with the same adverse effects.

In these cases of VAED, the underlying causes remain to be further understood, but possibly relates to an abnormal T-cell (Th2) response.

Assessment and evaluation

It can be difficult to distinguish between vaccine-failure (also known as breakthrough disease) and VAED. Identification of a case of VAED requires the recognition that a clinical presentation is different, atypical, modified or more severe in comparison to the natural disease presentation. Many factors need to be considered when making the assessment, including background rates, age, sex, time post vaccination, duration of disease, clinical course and progression and co-morbidities. Various laboratory and clinical diagnostic parameters can be used to help assess the possibility of VAED, including detailed review of all cases of possible vaccine failure.

Current National Immunisation Program (NIP) vaccines

The vaccines currently available through the NIP are not linked to VAED.

COVID-19 vaccines

There is no evidence to suggest VAED is associated with the current COVID-19 vaccines. On the contrary, more COVID-19 related morbidity and mortality has been observed in unvaccinated populations globally. Ongoing surveillance and long-term vaccine follow-up will continue.

Resources

• Brighton Collaboration: Vaccine-associated Enhanced Disease: Case Definition and Guidelines for Data Collection, Analysis, and Presentation of Immunization Safety Data
• CHOP: Antibody-dependent Enhancement (ADE) and Vaccines

Background

Vaccines work by activating an individual’s immune system to form antibodies and memory cells in response to a pathogen (disease-causing organism), without the individual having to be infected with that pathogen. This means that if or when that pathogen is encountered in the future, the immune system will be able to respond effectively to fight infection, either minimising the symptoms experienced or preventing disease altogether.

Vaccines can be categorised into types based on the technology that they use to initiate an immune response. This technology is referred to as a ‘vaccine platform’.

Inactivated vaccines

Inactivated vaccines are created by using killed or deactivated pathogens or parts of pathogens that are unable to replicate and cause symptoms of disease. This approach to vaccine manufacturing has been used for decades to produce vaccines such as those for hepatitis A and B, polio and the polysaccharide pneumoccal (Pneumovax 23) vaccine. Nuvaxovid (Novavax) is an example of an inactivated protein-based COVID-19 vaccine which utilises only part of the virus (the spike protein).

A benefit of these vaccines is that they are safe to administer to most people including pregnant or breastfeeding women or those with immunocompromise. However, the immune response induced by this mechanism alone may not be as strong or long-lasting compared with that from vaccines using other platforms. To overcome this challenge, booster doses or an adjuvant (ingredient added to vaccines during their manufacture to promote a stronger immune response and better disease protection) may be required.

Live-attenuated vaccines

Live-attenuated vaccines contain a whole pathogen that has been weakened (attenuated) in a laboratory making it less capable of replicating and causing disease. Examples of live-attenuated vaccines include the measles, mumps, rubella, varicella (chickenpox) and rotavirus vaccines.

Live-attenuated vaccines typically induce a strong immune response and provide long-lasting immunity meaning fewer doses are required. The main disadvantage of using this platform is that these vaccines are not recommended for use in people who are immunocompromised due to the theoretical risk of causing vaccine-associated disease or to pregnant women due to the potential harm to the unborn baby. In addition, they take longer and are more difficult to mass produce because the pathogen needs to be grown under enhanced biosafety protocols in specialised laboratories.

Genetic vaccines

Genetic vaccines use one or more of a pathogen’s genes (DNA or mRNA) to invoke an immune response. The COVID-19 vaccines Corminaty (Pfizer) and Spikevax (Moderna) are examples of mRNA vaccines and they contain the genetic code specific to the spike protein portion of the virus.

Genetic vaccines can be produced faster than traditional manufacturing methods as development can begin as soon as the genetic sequence of a pathogen is available. Genetic vaccines are only capable of producing proteins and are unable to modify the host’s (vaccine recipient) own genetic material (DNA or mRNA).

Viral vector vaccines

Non-replicating and replicating viral vector vaccines are types of genetic vaccines. They work by using a modified virus (viral vector), which doesn’t cause disease in humans, to carry a portion of the pathogen’s genetic code into human cells.

In non-replicating viral vector vaccines, the individual’s cells will then produce proteins (antigens) specific to the pathogen to trigger an immune response. The COVID-19 vaccine Vaxzevria (AstraZeneca) is an example of a non-replicating viral vector vaccine.

Replicating viral vector vaccines have a similar mechanism but will also create new viral particles to enter further human cells, allowing a quicker and stronger immune response. Replicating viral vector vaccines best mimic natural infection and hence produce a strong immune response and can be used in lower doses.

While viral vectors are well tolerated and highly immunogenic in most people, pre-existing immunity to the viral vector used may hamper the immune response to the vaccine.

Nanoparticle-based vaccines

Nanoparticle-based vaccines have received increasing interest in recent years due to their good safety profile and high immunogenic potential.

Nanoparticle vaccines are constructed by attaching selected key components of a pathogen (such as the COVID-19 spike protein or viral DNA) to an engineered nanoparticle (nanocarrier). This nanoparticle is commonly an engineered virus-like particle (a molecule that mimics the virus but is not infectious). These nanoparticles are highly stable and less prone to degradation than traditional protein vaccines. Gardasil 9 (human papillomavirus) and Nuvaxovid (Novavax COVID-19) vaccines are examples of this approach.

Resources

• Australian Immunisation Handbook: Types of vaccines
• Children’s Hospital of Philadelphia, Vaccine Education Centre: Making vaccines: How are vaccines made
• Frontiers in Immunology: Progress and Pitfalls in the Quest for Effective SARS-CoV-2 (COVID-19) Vaccines

Each local council throughout Victoria offers regular immunisation sessions for the administration of all funded National Immunisation Program (NIP) vaccines. Sessions are free to attend and people of all ages requiring NIP vaccines can be vaccinated. Sessions are run by accredited nurse immunisers with medical support. Some councils may also choose to have additional vaccines such as meningococcal (Nimenrix® or Bexsero®), influenza and chickenpox vaccines available for purchase for those who do not meet the eligibility criteria for funded vaccines [see resources]. All vaccines administered are recorded on the Australian Immunisation Register (AIR).

Please refer to the tables below for contact details of your local council to obtain further information regarding session times.

Metropolitan councils

Regional councils

For any feedback relating to this page please contact us here.

Resources

• DHHS: Victorian immunisation schedule and eligibility criteria for free vaccines
• MVEC: Australian Immunisation Register

At MVEC we strongly encourage people to seek answers to their questions and to be well informed with evidence-based information. We know that nearly half of all parents have some concerns about immunising their children, ranging from minor concerns to more serious degrees of vaccine hesitancy. Many people also have questions about COVID-19 vaccines for themselves and their families.

There is a lot of information available to people, particularly on the internet, which can be quite overwhelming. There is also a lot of misinformation, and conspiracy theories, and it can be hard to know which information sources to trust and what is true. Research suggests that information alone is not enough to address people’s concerns about immunisation, even when it comes from recommended sources. That is because vaccine conversations matter, and how we discuss vaccines is often just as important as what information is shared.

Talking to people who have questions about vaccines

One of the most effective strategies to address people’s questions and concerns about vaccines is through a discussion with a trusted health care provider like a GP, nurse, paediatrician or midwife. Effective conversations are non-judgemental and help guide people towards accepting vaccination.

Having a combative conversation with a person who has questions about vaccines is never helpful. If possible, try to work out where the person may sit on the vaccine hesitency spectrum. They may have only minor concerns, more serious concerns or they may refuse vaccines all together. This often becomes apparent quite quickly as you start the conversation and helps you tailor your conversation accordingly.

Here are the key steps to have an effective vaccine conversation:

1. Find out all of the person’s questions and concerns

• Start with an open-ended question, like “What concerns do you have?”
• Try to just listen and not jump in and correct their beliefs straight away. This is what we call “resisting the righting reflex”
• Encourage them to share all their concerns before you start responding. They may even mention their most important concern last.
• At this point, once they have had a chance to list their concerns, summarise them to check your understanding.

2. Acknowledge concerns and share knowledge

• Not everyone is “vaccine hesitant”. Having questions is very normal, especially with the newer COVID-19 vaccines. People are likely to be more receptive to what you have to say if you acknowledge their concerns without judgement.
• It is helpful to ask if you can share what you know about vaccine safety and effectiveness and provide some good resources and information. Try to keep your explanations clear and check for understanding.
• At this point, it is good to reinforce their motivation to accept vaccination.

3. Discuss disease severity

• It is always good to bring the discussion back to centre on disease severity, rather than focusing exclusively on the vaccines. This reminds people why we are vaccinating and reinforces the benefit.

4. Recommend vaccination

• Lastly, make a clear and strong recommendation to have the vaccine(s). This reinforces the importance of vaccination and clearly shows that you believe this is the best way to protect the person against vaccine preventable diseases.
• If it is possible and the person is willing, deliver the vaccine(s) or explain where they need to go to receive them.

5. Continue the conversation

• If the person is not yet ready to accept vaccination, keep the communication open and invite them back at a later time to continue the conversation.

Talking with friends and family can also have an influence on people’s vaccine hesitancy. If you’re someone who wants to encourage others to vaccinate, you can take some of the strategies we recommend for healthcare providers into your discussions with people in your life.

This seems obvious, but the best approach is not to judge people, correct them, or jump into battle. This just entrenches people’s beliefs and makes them defensive. And they probably won’t trust you or want to talk to you openly about this topic anymore!

How to tackle misinformation

We’ve all heard people spreading misinformation and myths about vaccines. While it can be tempting to try to correct misinformation whenever you hear it, this can actually give the issue more oxygen. But if you notice that misinformation is spreading widely and beginning to affect people’s vaccination behaviour, it may be time to step in.

If an individual is spreading misinformation, try to speak with them privately. It’s not effective to have a public debate, either in person or online. Acknowledge the emotion and try to look for the truth together.

If you are debunking a particular myth, start by clearly restating the truth. Then, explain why the myth is untrue, and provide an alternative explanation for what the person is experiencing.

For example, if someone believes that the flu vaccine gives them the flu because they feel sick after the vaccine, it’s not enough to simply tell them that is untrue. Explain why this is untrue – the vaccine contains a killed virus that cannot cause the flu. Then follow this with an alternative explanation for the person’s symptoms – this is your body generating an immune response to the vaccine, and these symptoms are much more mild and brief than actual flu symptoms.

Finally, end by restating the truth. People remember what we say first and last, and what we say more than once. Make sure it’s the truth and not the myth that sticks in their minds.

Resources

Talking to people who have concerns

• NCIRS Sharing Knowledge About Immunisation (SKAI) project
• MumBubVax: Talking about immunisation for mothers and babies
• The Conversation: Everyone can be effective advocate for vaccination- here’s how

Communicating about COVID-19 vaccines and vaccine safety

• World Health Organization: COVID-19 vaccines- safety surveillance manual
• Pre print MJA: Communicating with patients and the public about COVID-19 vaccine safety: recommendations from the Collaboration on Social Science in Immunisation
• COSSI: A COVID-19 vaccine strategy to support uptake amongst Australians: Working Paper November 2020
• ABC news: How to talk to friends and family feeling unsure about COVID-19 vaccines
• The COVID-19 Vaccine Communication Handbook

Addressing misinformation or talking about vaccination in online forums

• World Health Organization: How to respond to vocal vaccine deniers in public
• BMC Public Health: How organisations promoting vaccination respond to misinformation on social media: a qualitative investigation
• UNICEF: Vaccine misinformation management guide
• Tips on countering conspiracy theories and misinformation

What is it?

Varicella (chickenpox) is a highly contagious disease caused by infection with the varicella-zoster virus (VZV). After a person recovers, the virus stays dormant (inactive) within the dorsal root ganglia of the spinal nerves and can later be reactivated, presenting as herpes zoster (shingles). 

What to look for

Symptoms begin 7 to 21 days after exposure to the virus. Fever, rhinorrhoea (runny nose) and lethargy lasting 1 to 2 days are the first signs of disease (prodromal period). This is followed by the appearance of a pruritic (itchy) rash which is initially maculopapular (flat discoloured areas and raised areas) then becomes vesicular (fluid-filled blisters). The vesicles rupture then crust over, usually within 10 to 14 days. The rash can cover any part of the body including inside the mouth, on the scalp, eyelids and genital area. Unvaccinated children may experience 200 to 500 lesions. Approximately 5% of cases will be subclinical (symptoms are so mild they remain undetected under clinical examination).  

Most cases of varicella are self-limiting (will resolve by itself), but complications can include secondary bacterial infections, septicaemia (blood infections), pneumonia, meningitis, encephalitis and acute cerebellar ataxia (uncoordinated muscle movements). 

Varicella infections during pregnancy can result in congenital varicella syndrome in the child. Symptoms of congenital varicella syndrome include skin scarring, eye anomalies, limb defects and neurological malformations. The risk of congenital varicella syndrome is higher when infection occurs in the second trimester. Infants who have been exposed to varicella through a maternal varicella infection can develop herpes zoster, but this is rare. 

Despite vaccination, some people may still develop disease if exposed to infection. This is known as breakthrough disease. Breakthrough varicella symptoms are usually mild. Patients are typically afebrile and develop fewer skin lesions. People experiencing breakthrough disease are contagious and can transmit disease to others. 

How is it transmitted?

Varicella is transmitted by inhaling respiratory droplets that are made airborne when an infected person coughs or sneezes. It can also be spread by direct contact with the fluid inside the vesicles or through contact with items that have been contaminated with vesicle fluid. 

A person with varicella is considered infectious for 1 to 2 days prior to the onset of the rash until all the lesions have crusted. 

Epidemiology

Varicella is highly infectious. More than 80% of non-immune household contacts of an infected individual will develop disease.  

Prior to the introduction of vaccination in Australia in 2005, there were 240,000 cases of varicella annually, resulting in 1,500 hospitalisations and an average of 7 to 8 deaths. The rate of hospitalisation for varicella infection was reduced to 2.1 per 100,000 people in 2013. Most of these children were aged under 18 months, the scheduled age for varicella vaccination. (NB: Children can be safely vaccinated from 9 months of age.) 

Infants less than 4 weeks of age, premature neonates, unimmunised adolescents, pregnant women and immunosuppressed individuals are at the greatest risk of severe disease and complications if they become infected. 

Prevention

Vaccines can provide protection against varicella infection. 

^ MMRV combination vaccines must not be given as the first dose of measles-containing vaccine in children < 4 years due to the higher rates of fevers (see precautions and contraindications below).
* Whilst not registered for use in those aged ≥ 12 years, ATAGI recommends it may be used up to 14 years. MVEC advises that its use may also be considered in older adults when protection against measles, mumps and rubella is also required.
shaded boxes – varicella vaccine is routinely offered on the NIP as a single dose at 18 months. AIR will consider vaccination from 12 months of age as a valid dose.
shaded boxes not registered for use in this age group.
shaded boxes indicate live-attenuated vaccines.

Recommendations

A single dose of varicella vaccination (in combination with measles, mumps and rubella) is funded on the NIP at 18 months of age. (NB: Children can be safely vaccinated from 9 months of age.)

A second dose (not funded) is recommended for greater protection to reduce the incidence of breakthrough disease. A minimum interval of 4 weeks is recommended between doses of live-attenuated vaccines.

Anyone non-immune aged 14 years and over should receive a catch-up course of 2 doses (administered 4 weeks apart) for adequate protection.

Household contacts of immunocompromised individuals are recommended to complete their immunisation schedule on time.

Common vaccine side effects

Injection site reactions (occurring in the first 48 hours) and fever (occurring 5 to 12 days after vaccination) are common side effects.

A maculopapular or vesicular rash (with 2 to 5 lesions) occurring 5 to 26 days after vaccination will develop in approximately 5% of vaccine recipients. If this occurs, it is recommended that lesions should remain covered until they crust over to avoid potential transmission of the virus to others. Transmission of the vaccine virus to contacts is extremely rare. Worldwide there have only been 11 documented cases of virus transmission from a recently vaccinated person to unvaccinated individuals.

Precautions and contraindications

All varicella vaccines are live-attenuated vaccines and are therefore contraindicated in pregnancy and in those with immunocompromise.

Children and adults who have been diagnosed with IFNAR1 should seek advice from an immunisation specialist or immunologist prior to vaccination.

There are recommended intervals between immunoglobulins or other blood products and administration of injected live-attenuated vaccines. Refer to MVEC: Live-attenuated vaccines and immunoglobulins or blood products.

When administered as the first dose of an MMR-containing vaccine, MMRV vaccines have been associated with higher rates of fever in children. It is therefore recommended that MMRV vaccines are administered as the second dose only of the 2-dose course of MMR in children under 4 years of age.  

Post-exposure prophylaxis

Vaccination (first or second dose) can be provided within 3 to 5 days of exposure to varicella (provided it is not contraindicated). This can reduce the likelihood of varicella disease developing. 

Neonates (whose mother develops infection up to 7 days prior to delivery or within 2 days after delivery), infants under 1 month of age (if mother is seronegative), pregnant women, premature infants (while still hospitalised, regardless of maternal serology) or immunosuppressed individuals who are exposed to varicella disease should receive Zoster Immunoglobulin (ZIG). 

Repeat doses of ZIG may be given if a person is exposed to varicella again more than 3 weeks after the first dose of ZIG.

Resources

• RCH Kids health information: Varicella fact sheet
• Australian Immunisation Handbook: Varicella
• MVEC: Zoster
• MVEC: Live-attenuated vaccines and immunoglobulins or blood products