What is it?

COVID-19 disease is caused by the highly contagious SARS-CoV-2 virus, a type of coronavirus discovered in 2019 that spread rapidly resulting in a global pandemic. Multiple strains of SARS-CoV-2 have since emerged and public health authorities continue to monitor these. The Omicron strain is currently the most dominant variant circulating and has been shown to be more transmissible than previous variants.

COVID-19 disease has had vast impacts on society. In addition to the public health implications, the economic, social and mental health effects have been and continue to be enormous. 

What to look for?

Infections can be asymptomatic or can result in a spectrum of symptoms, from mild respiratory symptoms to more serious disease affecting multiple organs and systems. Severe disease can lead to hospitalisation and mechanical ventilation, or even death.  

Common symptoms of acute COVID-19 infection can include fever, cough, myalgia (body aches), dyspnoea (difficulty breathing), gastrointestinal symptoms (e.g., diarrhoea, nausea or vomiting), headache, sore throat, loss of smell or taste, and rhinorrhoea (runny nose).  

Some individuals can experience ongoing symptoms for weeks or months after their initial diagnosis, this is known as long COVID or post-COVID conditions. Symptoms can include extreme fatigue, post-exertional malaise, dyspnoea, chest pain, palpitations, fever, arthralgia (joint pain), paresthesia (pins and needles), rash, hoarse voice, problems with memory and concentration (brain fog), sleep problems, changes with taste or smell, gastrointestinal symptoms, changes in menstrual cycles, weight loss and poor appetite, mood changes (depression, anxiety), and difficulty completing activities of daily living. In addition, long COVID can have a huge impact on an individual’s quality of life, mental health, and ability to participate in work or schooling. Long COVID is more common in people who have experienced severe COVID-19 disease, those who had underlying medical conditions prior to infection (e.g., hypertension, chronic lung disease, diabetes, obesity), and those who are unvaccinated.

Paediatric Multisystem Inflammatory Syndrome Temporally associated with SARS-CoV-2 (PIMS-TS), or Multisystem Inflammatory Syndrome in Children associated with COVID-19 (MIS-C), is a newly described condition that has been reported in children in the first 2-6 weeks after COVID-19 infection. It is an inflammatory condition, similar to Kawasaki disease, and is characterised by rash, fever, shock and abdominal pain. Children experiencing PIMS-TS almost always require hospitalisation for treatment.

How is it transmitted?

Transmission of COVID-19 is through the inhalation of virus particles which have been made airborne after an infected person coughs, sneezes, breathes, speaks or sings. Droplets or particles can contaminate surfaces and can be spread when a person touches these surfaces and then touches their nose, mouth or eyes. Poorly ventilated settings can also contribute to the spread of COVID-19 as it means aerosol particles can remain suspended in the air for minutes to hours.

The incubation period for the disease is 1-14 days, with most individuals displaying symptoms 5-6 days after being exposed. Individuals are thought to be infectious up to 48 hours before symptoms appear and are most infectious in this prodromal period and the early stages of their illness. People with asymptomatic disease can still infect others.  


Since 2019, over 765 million infections have been reported worldwide contributing to almost 7 million deaths, with true figures likely to be much higher. 

Individuals with immune compromise (due to taking specific medications/therapies or due to a medical condition), advancing age (particularly > 70 years), obesity, respiratory conditions, pregnancy, heart disease, diabetes, renal disease, liver disease, neurological conditions and disability are more likely to experience severe symptoms if infected with SARS-CoV-2.

Certain occupations, such as working in health care, carry a greater chance of exposure to SARS-CoV-2 and therefore infection.


Strategies to reduce risk of transmission of COVID-19 disease include standard precautions such as hand hygiene, wearing a mask indoors when remaining socially distant is not possible, and ensuring good ventilation. Vaccines can reduce the severity of COVID-19 symptoms and need for hospitalisation.

Primary course

A primary course of vaccination is recommended for all individuals from 5 years of age. Immune competent (those with a functioning immune system) individuals should receive 2 doses given 8 weeks apart, whereas those with immunocompromise should receive 3 doses, with 8 weeks between each dose.

Children aged 6 months to ≤ 4 years with severe immunocompromise, disability, and those who have complex and/or multiple health conditions which increase the risk of severe COVID-19 should also receive a primary course of COVID-19 vaccination. In this age group a primary course consists of 3 doses of Comirnaty (Pfizer) [maroon cap] with 8 weeks between each dose, regardless of immune function.

Booster doses

In 2023 ATAGI recommends a single COVID-19 booster dose for all adults aged 65 years and over, as well as adults aged 18-64 years with medical comorbidities that increase their risk of severe COVID-19 disease.

Adults aged 18-64 years (without risk factors for severe COVID-19 disease), and children and adolescents aged 5-17 years (with medical comorbidities that increase their risk of severe disease or with disability or complex health needs) can consider a booster dose. Booster doses are not recommended in anyone less than 5 years of age.

Vaccines brands available for use by age group

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shaded boxes indicate preferred vaccine type used in each age group.
shaded boxes indicate that vaccine is not available for use in this age group.

Side effects following vaccination

Common side effects 

Most side effects following COVID-19 vaccination are mild and can include pain at the injection site, fatigue, headache, lymphadenopathy and fever. 

Rare side effects  

Myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the lining around the heart) are rare conditions that have been reported following administration of COVID-19 vaccines. They are most commonly associated with viral infections (including COVID-19 disease) but can also be triggered by other factors such as medications and autoimmune conditions. In the setting of vaccination, the peak risk group for myocarditis is young adult males aged between 16-24 years old following a second dose of vaccination. Pericarditis occurring after vaccination is more common in the 20-45 year old age group for both males and females. 

Thrombosis with thrombocytopenia (TTS) was a rare condition that was reported to occur in people who had previously received the COVID-19 vaccine Vaxzevria (AstraZeneca). From March 20, 2023 Vaxzevria is no longer available for use in Australia.

Commonly asked questions

  • Can pregnant or breastfeeding women receive COVID-19 vaccines?

    Yes it is safe to administer COVID-19 vaccines at any stage of pregnancy. Due to an increased risk of severe outcomes for pregnant women and their unborn babies it is recommended that pregnant women have received a primary course of COVID-19 vaccination. Administration of booster doses can also be considered if they are due.

    Breastfeeding women can receive COVID-19 vaccines. They do not need to stop breastfeeding before or after being vaccinated.

    Real world surveillance of international data on mRNA COVID-19 vaccine administration in pregnant women has shown no significant safety concerns for either the mother or the baby. Further to this, antibodies have been detected in the cord blood and breastmilk of vaccinated women, suggesting a transfer of protection to the baby.

  • Where can I access COVID-19 vaccines?

    COVID-19 vaccines can be accessed through GP clinics, some pharmacies (for vaccine recipients aged ≥ 5 years) and hospital immunisation services at Monash Children’s Hospitalthe Royal Children’s Hospital and Joan Kirner Women’s and Children’s Hospital (Sunshine). To find your closest provider and make an appointment visit the Health direct website or phone the coronavirus hotline on 1800 675 398.

  • What is the recommended interval between COVID-19 infection and vaccination?

    An interval of 6 months between COVID-19 infection and COVID-19 vaccination (primary dose or booster dose) is recommended.

  • Can COVID-19 vaccines be administered on the same day as other vaccines?

    In most instances COVID-19 vaccines can be co-administered (given on the same day) with other vaccines, and this includes influenza vaccines. The only exception to this is for children aged 6 months to < 5 years, where separating COVID-19 vaccines and other vaccines by 7-14 days is preferred. This recommendation aims to minimise adverse events such as fever, which can occur in the 3 days following inactivated vaccines and 7-10 days post vaccination with the live-attenuated MMR vaccine.

  • How do we complete a primary course of vaccination for children aged 6 months - ≤ 4 years who commenced their course with Spikevax (Moderna) `{`original/ancestral`}` now that it is no longer available?

    Immune competent children who commenced their primary course with 1 dose of Spikevax (Moderna), can complete their primary course with 1 dose of age-appropriate Comirnaty (Pfizer) only. Severely immunocompromised children who received 1 dose of Spikevax (Moderna), should receive a further 2 doses of Comirnaty (Pfizer) 8 weeks apart to complete the primary course. Severely immunocompromised children who received 2 doses of Spikevax (Moderna) should receive 1 further dose of Comirnaty (Pfizer) 8 weeks later to complete the primary course.


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

Reviewed by: Rachael McGuire (MVEC Education Nurse Coordinator)

Date: June 6, 2023

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.