Safety of COVID-19 vaccines

In Australia COVID-19 vaccines registered for use are required to undergo the Therapeutic Goods Administration’s (TGA’s) rigorous assessment and approval process to ensure compliance with our country’s strict standards on safety and effectiveness. The TGA releases a COVID-19 vaccine weekly safety report (external site) with updated reporting on side effects and adverse events.

Clinical guidance on COVID-19 vaccine in Australia

For COVID-19 immunisation providers and program staff: The Australian Technical Advisory Group (ATAGI) Clinical guidance for COVID-19 vaccine providers (external site).

Information for health professionals on allergy and COVID-19 vaccination: See the Australasian Society of Clinical Immunology and Allergy (ASCIA) Guide: Allergy and COVID-19 Vaccination (external site).

Potential side effects from COVID-19 vaccines

Most side effects from a COVID-19 vaccine are mild and transient. Reactions at the injection site such as redness, swelling, pain and systemic symptoms, like headaches, fever, muscle aches and fatigue, are very common within the first 48 hours. Serious adverse events attributable to vaccination are very rare.

Of note, respiratory symptoms (e.g. cough, runny nose etc.) are not side effects of the vaccine. People with respiratory symptoms should be tested for COVID-19.

Myocarditis and/or pericarditis

The Australian Technical Advisory Group on Immunisation (ATAGI) and the Cardiac Society of Australia and New Zealand (CSANZ) have recently updated the Guidance on Myocarditis and Pericarditis after COVID-19 Vaccinations (external link).

Myocarditis and/or pericarditis are rare side effects that have been associated with all brands of COVID-19 vaccine currently used in Australia. The available data suggests the risk is higher after an mRNA vaccine and is greater following Spikevax (Moderna) compared to Comirnaty (Pfizer).

Pericarditis and myocarditis after COVID-19 vaccines have been mostly reported in males aged 16-40 years of age, and mostly after the second dose. However, these conditions do occur in both females and males, at any age, and after any dose, including a third or fourth dose.

The WA Department of Health accordingly advises the following:

  • Myocarditis and pericarditis following vaccination can present with atypical features, such as the absence of chest pain, or the presence of abdominal pain or other non-specific symptoms. It is important to consider myocarditis in the differential diagnosis if someone presents with ongoing non-specific symptoms in the 1-2 weeks following a COVID-19 vaccine.
  • Providers should consider the potential risk of myocarditis and pericarditis when selecting a COVID-19 vaccine brand and dose interval, considering the individual’s age, gender, preferences, and any precautions in relation to specific vaccine brands.
  • ATAGI recommends an 8-week interval between dose one and dose two for the Pfizer, Moderna and Novavax vaccines, particularly for males aged 12 to 39 years. This may reduce the risk of myocarditis and/or pericarditis following vaccination.
  • Most myocarditis cases linked to COVID-19 vaccination have required hospitalisation, with most cases having a relatively mild and self-limiting course. Fatal cases have been reported, including in females.
  • Patients with confirmed myocarditis should be admitted to hospital for cardiac monitoring, until the cardiac biomarker levels have peaked, and symptoms have improved.
  • Pre-existing cardiac conditions are not regarded as a contraindication to vaccination.
  • People with a history of any of the following conditions can receive an mRNA vaccine (e.g. Comirnaty or Spikevax) but should consult a GP, immunisation specialist service or cardiologist about the best timing of vaccination and whether any additional precautions are recommended:
    • Recent myocarditis or pericarditis (within the last 3 months)
    • Acute rheumatic fever or acute rheumatic heart disease (i.e., with evidence of active inflammation)
    • Acute decompensated heart failure

For more information see ATAGI’s COVID-19 vaccination – Guidance on myocarditis and pericarditis after COVID-19 vaccines (external site).

Adverse events after COVID-19 vaccine Vaxzevria (AstraZeneca)

People who have had the first dose of AstraZeneca without any serious adverse effects can safely be given the second dose, including adults under 60 years.

Mixed dosing

It is recommended people have the same vaccine brand for the first and second dose.

However, an alternative vaccine can be offered for the second dose in some circumstances, including:

  • Severe side effects after the first dose - there are medical contraindications or precautions to a vaccine,
  • Overseas vaccines - the original vaccine is not available in Australia,
  • Lack of access - a person is unable to access a particular vaccine
  • Personal preference - a person is not accepting of a second dose of the same brand

If you have questions about switching brands between your first and second dose of COVID vaccine you should discuss it with your health care provider.

For further information, see COVID-19 vaccination – ATAGI Clinical advice on the use of a different COVID-19 vaccine as the second dose (external site).

Reporting adverse events following immunisation (AEFI)

Healthcare providers should report:

  • any significant (or rare and unexpected) AEFIs in both children and adults
  • any vaccine reaction that requires assessment by a doctor or nurse
  • any vaccine reaction that has affected a family’s confidence in future immunisation.

You can report adverse events even if you are not sure whether the vaccine caused the event.

Health care providers and members of the public can report possible AEFI using the online portal at SAFEVAC-WAVSS (external site).

For further information see adverse events following immunisation in WA.

Last reviewed: 01-11-2022