Australia’s trusted independent immunisation experts

We have provided answers to some of the most frequently asked questions about COVID-19 vaccines. We will be updating this page regularly (last updated 1 March 2021).

Questions about vaccination program

  • Which COVID-19 vaccines will be used in Australia in 2021?

    The Australian Government COVID-19 vaccination program commenced on 22 February using Comirnaty (also called BNT162b2), developed by Pfizer and BioNTech. This mRNA COVID-19 vaccine was provisionally approved for use in Australia in January 2021.

    The Therapeutic Goods Administration (TGA) has also given provisional approval to the AstraZeneca/Oxford University vaccine, called COVID-19 Vaccine AstraZeneca, developed by AstraZeneca and the University of Oxford. This is a viral vector vaccine, and it is likely to be rolled out from early March 2021. 

    The Australian Technical Advisory Group on Immunisation (ATAGI) has provided clinical guidance on the use of both these vaccines. 

    The Australian Government has a third advance purchasing agreement for the supply of Novavax’s NVX-CoV2373 COVID-19 vaccine, an adjuvanted protein vaccine. This agreement and rollout of vaccine will only proceed if the vaccine meets acceptable effectiveness and safety standards and is approved by the TGA.  

    In addition, Australia is a member of the COVAX Facility, a global collaboration to invest in COVID-19 vaccines and ensure they are distributed equitably. Through the COVAX Facility, the Australian Government has made an upfront payment to secure enough doses for up to 50% of the Australian population to be vaccinated. Read more about the COVAX Facility here

    The government has also made commitments to support access to safe and effective COVID-19 vaccines for countries in the Pacific and Southeast Asia.

  • When will COVID-19 vaccines be available in Australia?

    A staged rollout of the COVID-19 vaccines started from 22 February 2021. Information about the proposed roll out, including a list of priority groups, is available here

    Refer also to the question: Who will get a COVID-19 vaccine first and how is this decided?

  • Who will get a COVID-19 vaccine first and how is this decided?

    It will take time for enough vaccine doses to be manufactured so that the entire population in Australia can be vaccinated. Initially, the vaccine will be offered using a 'priority framework' that outlines how to allocate the initially limited available doses. 

    The Australian Government, informed by ATAGI and other medical expert groups, has published detailed information outlining priority populations on the basis of a number of factors, including where COVID-19 infections are occurring, the risk of infection and severe disease, and the characteristics of the available vaccines. 

    Similar priority lists have been developed around the world, including by the World Health Organization, the United Kingdom Joint Committee on Vaccination and Immunisation and the United States Centers for Disease Control and Prevention. 

    As quarantine and border workers, frontline health care workers and aged care and disability care staff workers are at high risk of contracting COVID-19 and also may spread the virus to vulnerable patients and the elderly, they have been identified as groups to be offered the vaccine first, along with aged care and disability residents. 

    Children are not an initial priority group for COVID-19 vaccination because of lesser disease severity in children than in older people.

  • Where will people be able to access the vaccine, and will it be free?

    COVID-19 vaccines are free for everyone in Australia, as per the Australian COVID-19 Vaccination Policy

    The Australian Government has published information on the vaccination sites, noting some of this is still to be finalised.

    As there will be limited initial supplies of the vaccine, priority groups will be offered the Pfizer vaccine first via hubs, usually in urban and rural locations, around Australia, with vaccination teams also going out to aged and disability care facilities.

    As the roll out continues, the Astra Zeneca vaccine will become available at other locations including GP respiratory clinics, General Practices (that meet specific requirements), Aboriginal Controlled Community Health Services, state-run vaccination clinics, and eventually at some workplace vaccination sites and community pharmacies that meet specific requirements. 

  • Will the COVID-19 vaccine be mandatory?

    The Australian Government has stated that COVID-19 vaccination “is not mandatory and individuals may choose not to vaccinate”. If people choose not to have a COVID-19 vaccine, this will not affect their family’s eligibility for Family Tax Benefit Part A or childcare fee assistance which only includes National Immunisation Program vaccines for those aged <20 years.

    It is possible that in future, vaccination against COVID-19 may become a requirement for travel to certain destinations or for people working in certain high-risk workplaces. If this becomes the case, it is anticipated there will be exemptions in place for people who are unable to be vaccinated.

  • What is herd immunity and how does it relate to the COVID-19 vaccination program?

    Herd immunity occurs when enough people are vaccinated to prevent the coronavirus (SARS-CoV-2) that causes COVID-19 from easily spreading from person to person. Eventually, most of the population may be able to be protected from a particular disease if the vaccine is sufficiently protective and enough people in the population are vaccinated. 

    Achieving herd immunity usually requires a large proportion of the population to be vaccinated. The exact proportion of the population that need to be vaccinated to affect the spread of the SARS-CoV-2 virus depends on characteristics of the virus (e.g. how easily it is transmitted) and characteristics of the vaccine (e.g. its ability to stop transmission, and duration of protection). 

    It is easier to generate herd immunity with a vaccine that provides long-term protection and that prevents transmission of the infection between people. Vaccines that provide short-term protection require booster doses, making herd immunity harder to achieve. 

    How many people in the population that need to be vaccinated to reduce the spread of the virus is not easy to predict – it is best observed in ‘real time’. 

    As we learn more about the characteristics of COVID-19 vaccines and how well they protect against the disease and spread of the virus, many studies will be done to monitor how much impact the vaccines have and whether herd immunity is being developed over time. 

  • Which COVID-19 vaccines are already in use in other countries?

    As of 16 February, almost 200 million COVID-19 vaccines have been given to people worldwide.

    As of 12 January 2021, Pfizer/BioNTech’s vaccine has received temporary or emergency use authorisation in the UK, Bahrain, Canada, Mexico, the USA, Singapore, Chile, Oman, Saudi Arabia, the European Union and by the World Health Organization. The University of Oxford/AstraZeneca vaccine has received temporary or emergency use authorisation in the UK, India, Argentina, Dominican Republic, El Salvador, Mexico and Morocco.

    Several other vaccines are reportedly in use in other countries including:

    • Sinovac Biotech’s inactivated vaccine, which received Emergency Use Authorisation in China
    • Gamaleya Institute’s viral vector vaccine, which was approved for public use in Russia
    • Sinopharm’s inactivated vaccine, which received Emergency Use Authorisation in Bahrain and in the United Arab Emirates
    • CanSino’s viral vector vaccine, which was approved for military use in China.

    Further information and updated advice is provided by the Strategic Advisory Group of Experts on Immunization (SAGE) here.

  • Will we still need other COVID-19 prevention measures like social distancing and lockdowns if a COVID-19 vaccine is available?

    Australia will still need to keep the flexible and extensive strategies already in place to control COVID-19 during the early months of vaccine program. Once the vaccine is able to be given to a high proportion of people, it is anticipated that we will be able to reduce some of these control measures. 
    This is likely to be a step-wise process, done cautiously, and will rely on many people being willing to have the vaccine. 

  • Why are multi-dose vials being used to store COVID-19 vaccines?

    Multi-dose vials contain more than one dose of a vaccine in a single glass vial. They usually include 5–20 doses per vial, and each dose is then carefully extracted and given via individual syringes for injection. Use of multi-dose vials is the most efficient way to distribute a new vaccine to the maximum number of people and is being used world-wide for all COVID-19 vaccines. 

    Packaging vaccine doses multi-dose vials is safe and is supported by numerous quality controls and good handling practices. 

    Multi-dose vials are routinely used in Australia for the tuberculosis (BCG) vaccine and were used for the 2009 pandemic influenza vaccine. Immunisation providers are trained in and follow guidelines specifically on the use of multi-dose vials.

Questions about getting vaccinated

  • Why should I get a COVID-19 vaccine?

    COVID-19 is a disease caused by the virus SARS-CoV-2. It can cause severe lung and generalised disease and has caused the deaths of over 2 million people worldwide since January 2020.

    Although the elderly and people with underlying medical conditions are at higher risk, anyone can get severe disease and die of COVID-19. In some people, COVID-19 may cause long-term symptoms of fatigue and breathlessness. The virus is also easily spread by people with few or no symptoms; even if you may not become unwell with COVID-19, others you may pass on the virus to can. 

    By vaccinating, you are protecting yourself and others from severe COVID-19. It is also likely that once a large amount of people are vaccinated, this will decrease the spread of COVID-19 in our community. 

  • Can I choose which COVID-19 vaccine I get?

    You will not be able to choose which COVID-19 vaccine you are offered. 

    Initial supply of COVID-19 vaccines will be limited, and whichever vaccine is available will be first offered to people with the highest risk of getting, spreading or having severe illness from COVID-19 and then more broadly to the rest of the adult community. 

  • What is Comirnaty and how does it work?

    Comirnaty, also called BNT162b2, is a COVID-19 vaccine developed by Pfizer and BioNTech. It is an mRNA vaccine that contains the genetic code for an important part of the COVID-19 virus called the ‘spike protein’. After getting the injection, your body reads the genetic code and makes copies of the spike protein. Your immune system then detects these spike proteins and learns how to recognise and fight against COVID-19. 

  • What is COVID-19 Vaccine AstraZeneca and how does it work?

    COVID-19 Vaccine AstraZeneca is a COVID-19 vaccine developed by The University of Oxford and AstraZeneca. It contains a harmless common cold ‘carrier’ virus (an adenovirus), into which the genetic code for the SARS-CoV-2 spike protein has been inserted. The spike protein is an important part of the SARS-CoV-2 virus and helps the virus enter cells. 

    After vaccination, the adenovirus carrier brings this piece of genetic code into your cells, and your cells then read it to produce copies of the spike protein. Your immune system then detects these spike proteins and learns how to recognise and fight against COVID-19. 
    The adenovirus has been modified so that it cannot replicate once it is inside cells. This means that it cannot spread to other cells and cause infection. For this reason, COVID-19 Vaccine AstraZeneca is not considered a ‘live vaccine’. 

  • How many doses of COVID-19 vaccine will be required and what will be the schedule?

    The number and timing of doses will vary between different COVID-19 vaccines and you should follow the guidance of your immunisation provider. 

    If you are having Comirnaty (Pfizer), you will need to have two doses, around 3 weeks apart. 

    The AstraZeneca/University of Oxford COVID-19 vaccine also requires two doses, given around 12 weeks apart (or as short as 4 weeks apart, if necessary). 

    Refer to ATAGI clinical guidance on COVID-19 Vaccine in Australia in 2021 for more details on dose timing.


  • Can COVID-19 vaccines be co-administered with other vaccines (eg, influenza vaccine)?

    Routine administration of a COVID-19 vaccine on the same day as another vaccine, including an inactivated influenza vaccine, is not recommended. Currently the preferred minimum interval between receipt of COVID-19 vaccine and another vaccine is 14 days. 

    This advice may change as further information becomes available.

    For more information, refer to ATAGI clinical guidance on COVID-19 Vaccine in Australia in 2021.

  • How effective are COVID-19 vaccines?

    Several vaccine developers have made preliminary announcements about the efficacy of their COVID-19 vaccine in phase 3 clinical trials, and some have published early (interim) results. 

    These results are very promising, and indicate that each of these vaccines is able to prevent COVID-19 disease to a statistically significant degree. 

    Comirnaty (made by Pfizer) is about 95% effective at preventing people from getting sick with COVID-19, based on clinical trials and information from regulators. 

    COVID-19 vaccine made by AstraZeneca/University of Oxford is about 62-70% effective at preventing people from getting sick with COVID-19, based on clinical trials and information from regulators. 

    Initial clinical trial data for both the Pfizer and AstraZeneca/University of Oxford vaccine suggest very high protection (possibly close to 100%) against severe COVID-19. More data on this will come over time.

    The Novavax vaccine is about 89% effective at preventing people from getting sick with COVID-19, based on a press release from the company.

    At this stage it is unclear how long immunity from COVID-19 vaccines will last and how effectively they will decrease transmission (the spread of disease between people) – refer to question: What is herd immunity and how does it relate to the COVID-19 vaccination program?

  • Will the COVID-19 vaccines be effective on new variants of the virus?

    Certain viruses, including the novel coronavirus, SARS-CoV-2, naturally mutate over time. Often these mutations don’t impact on how viruses affect us. However, some recent variants of SARS-CoV-2 have meant that those strains are more easily spread.

    Current evidence from clinical trials indicates that the antibodies induced from COVID-19 vaccines are likely to provide protection to a variety of mutations and minor changes. However, in some cases there may be an impact on how antibody can ‘neutralise’ the virus and this may mean that the effectiveness of the vaccines against this particular strain could be affected. This information is still emerging and is being closely monitored. 

    In the same way that the influenza vaccine changes each season, the technology used to create the COVID-19 vaccines may be able to be adapted to changes in variants. 

  • How long will immunity from the COVID-19 vaccine last?

    As clinical trials are ongoing, and people have only started to be vaccinated in some other countries since around December 2020, we do not yet know how long immunity from the COVID-19 vaccine will last. 

    We will gather more information about the duration of protection over the coming months. 

    Refer also to What is herd immunity and how does it relate to the COVID-19 vaccination program?

  • Can different COVID-19 vaccines be used interchangeably?

    It is generally not recommended to use COVID-19 vaccines interchangeably, since we do not yet know whether this is effective.

    You should ideally have two doses of the same COVID-19 vaccine to complete your course.

    However, this advice may change over time as more data emerges. For example, a clinical trial of vaccination with alternating doses of Pfizer and AstraZeneca vaccines is being conducted in the United Kingdom.

  • Should I wait for a better COVID-19 vaccine?

    The COVID-19 vaccines we will have in Australia have already been shown to be safe and effective, and it is strongly recommended to get vaccinated as soon as you are offered a vaccine. 

    Having a COVID-19 vaccine now offers you and others protection against the disease and is the fastest way to reducing our need for strict COVID-19 related measures. 

    Having one course of COVID-19 vaccination now will not mean you will not be eligible to have another COVID-19 vaccine in future – it is possible that additional or booster doses of vaccine are needed in the future. More data will come on this over time. 

  • Do I need the vaccine if I have already had COVID-19 in the past?

    It is important that the COVID-19 vaccine is available to the entire population, even people with a past history of COVID-19. 

    The vaccine clinical trials included some previously infected people (who had a blood test showing past infection). These people responded to the vaccine well. They had a good immune response and had similar mild and expected side effects to people who weren’t previously infected.

    If you have previously been diagnosed with COVID-19, you should talk to your healthcare provider about the best time to have a COVID-19 vaccination. You may be advised to wait until around 6 months after you have recovered from COVID-19 to have your vaccine. 

  • What happens if I get COVID-19 between the first and second dose of a COVID-19 vaccine?

    Your body will develop an immune response within 2–3 weeks after the first dose and will be partially protected. However, all people need a second dose to achieve maximum and longer lasting protection. 

    Some people who have just had one dose of the vaccine may develop COVID-19 disease. If you are infected and have only had one dose of vaccine, you will still be able to have the second dose of COVID-19 vaccine, but you may be advised to delay the second dose for around 6 months after you have recovered from COVID-19.

    Some people may also develop COVID-19 disease after two doses; however, it is expected symptoms will not be severe. Further evidence is awaited that will provide more insight on this. 

  • How do I prepare for COVID-19 vaccination and what to do after COVID-19 vaccination?

    Refer to the preparing for COVID-19 vaccination guide on what to do before your vaccination. This provides information on what you should do before your COVID-19 vaccination as well as what to expect at your appointment.

    Refer to the after your COVID-19 vaccination guide for information on what to do after your vaccination. This provides a list of common side effects and what to do in the event of a side effect.

  • Can children have a COVID-19 vaccine?

    Children under 16 years of age cannot have Comirnaty, the Pfizer COVID-19 vaccine. Children and adolescents under 18 years of age cannot have the AstraZeneca COVID-19 vaccine. 

    This is because we don’t have any clinical trial results yet to confirm that the vaccines are effective and safe in these age groups. Clinical trials in children are planned or underway, and in the future children may be able to receive both of these vaccines.

  • From what age can a person with medical condition get a COVID-19 vaccine?

    People with specific underlying medical conditions will be eligible for access to COVID-19 vaccines once Phase 1b of the COVID-19 vaccine program commences. 

    People with chronic medical conditions can receive either Comirnaty (Pfizer) or COVID-19 Vaccine AstraZeneca. There is no preference for one vaccine over another in people with medical conditions and such people can access whichever vaccine is made available to them at a COVID-19 immunisation site.

    At the current time, the Comirnaty (Pfizer) vaccine is registered from ≥16 years of age and the COVID-19 Vaccine AstraZeneca is registered from ≥18 years. Thus, a 16- or 17-year old with a medical condition is eligible for Comirnaty for protection, and services should seek to ensure this can occur.

  • Can I have a COVID-19 vaccine if I am pregnant, breastfeeding or planning pregnancy?

    COVID-19 vaccines are not routinely recommended in pregnancy, because pregnant women have not been included in clinical trials. However, some pregnant women may still choose to be vaccinated after considering the benefits and risks of vaccination. 

    In particular, a pregnant woman may wish to be vaccinated if she has risk factors for severe illness from COVID-19 or if she is at high risk of exposure to COVID-19, for example, because of her occupation.

    Women who are breastfeeding can have a COVID-19 vaccine, and they don’t need to stop breastfeeding after vaccination. There are no theoretical safety concerns about the currently available COVID-19 vaccines for breastfeeding women or their babies. 

    Women who are planning pregnancy can have a COVID-19 vaccine, and they don’t need to avoid becoming pregnant after vaccination. 

    Either of the COVID-19 vaccines approved in Australia – Comirnaty (Pfizer) or COVID-19 Vaccine AstraZeneca – is suitable for women who are pregnant, breastfeeding or planning pregnancy. 

    For more information it is advised that women talk to their healthcare provider and refer to the COVID-19 vaccination decision guide for women who are pregnant, breastfeeding or planning pregnancy.

  • Can I have a COVID-19 vaccine if I am immunocompromised?

    Being immunocompromised means you have a weakened immune system, either from an underlying medical condition or from medical treatment that weakens your immune system. 

    If you are immunocompromised, you are strongly recommended to receive either of the COVID-19 vaccines currently approved in Australia – Comirnaty (Pfizer) or COVID-19 Vaccine AstraZeneca. The ATAGI clinical guidance on COVID-19 Vaccine in Australia in 2021 provides a list of medical conditions associated with increased risk of severe COVID-19 illness.

    Both of these vaccines are considered to be safe in immunocompromised people. However, they may be less effective in immunocompromised people, because the vaccines rely on your immune system to build a response. This means that it’s important to continue other protective measures against COVID-19, even if you are vaccinated. 

    Comirnaty (Pfizer) is not a live vaccine. COVID-19 Vaccine AstraZeneca contains a virus that is non-replicating and is also not considered to be a live vaccine, meaning that it cannot cause infection even in an immunocompromised person.

  • Can I have a COVID-19 vaccine if I have allergies?

    Almost all people with allergies can have a COVID-19 vaccine. 

    The only exception is if you have had anaphylaxis (a type of severe allergic reaction) to a previous dose of a COVID-19 vaccine or to one of its ingredients.

    If you have had anaphylaxis to another substance (including foods, drugs or insect stings), or if you have been prescribed an adrenaline auto-injector (Epipen), you may be advised to stay for 30 minutes after vaccination with a COVID-19 vaccine.

  • If I have an allergic reaction after a COVID-19 vaccine or to one of its ingredients, can I still have the second dose?

    If you have had anaphylaxis (a type of severe allergic reaction) to a previous dose of a COVID-19, or to one of its ingredients, you should not have that vaccine again. Your healthcare provider can help to determine whether it will be safe for you to have an alternative COVID-19 vaccine. 

    If you had a suspected allergic reaction which was not anaphylaxis after a COVID-19 vaccine, you may still be able to have the second dose of the vaccine, but in some cases precautions are needed such as a longer period of observation after vaccination or referral for allergy testing

    You can find out more about the ingredients in COVID-19 vaccines in the Consumer Medicine Information, which is available on the TGA website.

Questions about vaccine safety

  • Can you get COVID-19 from a COVID-19 vaccine?

    You cannot get COVID-19 from a COVID-19 vaccine. 

    To get COVID-19, a live virus that can multiply in your body has to infect you. No vaccine supplied currently in the world contains live coronavirus. 

    The vaccines used in Australia and elsewhere contain a genetic material that codes for the spike protein (eg, Pfizer and AstraZeneca), the spike protein itself (eg, Novavax) or an inactivated (or killed) form of the virus (in vaccines manufactured in China). 

  • What are the likely side effects from COVID-19 vaccines?

    All vaccines can cause side effects. Usually these are mild. Clinical trials of COVID-19 vaccines have reported side effects such as pain at the injection site, fever or muscle aches starting on the day or day after vaccination.  

    Comirnaty (Pfizer) is generally well tolerated and most side effects are mild and short-lived. The most common side effects include pain at the injection site, tiredness, headache, muscle pain, chills, joint pain and fever. These side effects were temporary and went away without treatment in 1-2 days.

    Refer to the after you COVID-19 vaccination guide for information on common and less common side effects.

  • What should I do if I have side effects after a COVID-19 vaccine?

    Your immunisation provider will tell you about the common symptoms you may experience after your COVID-19 vaccine. These may include pain, redness or swelling at the site of your injection. It may also include some general side effects such as tiredness, headache or fever. You can take paracetamol or ibuprofen to help with side effects like pain, headache or fever. 

    You should seek urgent medical assistance (e.g. by calling 000) if you think you are having a severe allergic reaction, such as if you are experiencing difficulty breathing, hives, lip swelling or feeling faint.

    You should seek advice from your usual healthcare provider (e.g. GP) if you have any side effects that you are concerned about, or if your side effects have not gone away after a few days.

    You can report potential side effects after vaccination to your state or territory health authority, or directly to the Therapeutic Goods Administration (TGA). Your healthcare provider can make the report for you if you wish. This will help the TGA collect information about adverse effects that occur after COVID-19 vaccination and detect any possible unexpected safety signals.

  • Do COVID-19 vaccines used in Australia contain pork gelatine?

    Comirnaty (Pfizer) and AstraZeneca/University of Oxford COVID-19 vaccine do not contain any gelatine. 

    List of ingredients for Comirnaty (Pfizer)

    List of ingredients for ChAdOx1-S (AstraZeneca/University of Oxford) 

    Once other vaccines are approved for use in Australia, a list of ingredients will be available for those vaccines too.

  • How is vaccine safety monitored after a vaccine is approved for use?

    After any vaccine is registered and it starts to be given to people, vaccination experts and regulators continue to monitor vaccine safety in several ways. People can report side effects or adverse events directly to the regulatory body, the TGA. This is called passive surveillance because it waits for people to report. As a further check, the TGA assesses the quality of every batch of vaccine before it can be supplied in Australia.

    There is also active surveillance where researchers or regulators actively seek out any side effects in large groups of people given the vaccine. One form of active surveillance is where researchers continue to study the vaccine’s effectiveness and safety (sometimes called ‘phase 4’ trials). Another form is using established systems such as AusVaxSafety, in which clinics send SMS messages to people receiving vaccines (or their parents or carers) to ask if they had any reactions after receiving a vaccine. Independent experts analyse the responses to make sure that any safety issues are detected quickly. AusVaxSafety operates in almost 300 clinics around Australia and cover hundreds of thousands of people.

    The systems described above will be used and expanded to monitor vaccine safety for all licensed COVID-19 vaccines, with experts meeting to review all reported data even more frequently than for usual vaccines.

  • Are shortcuts being taken in vaccine safety assessment?

    No. Although COVID-19 vaccine trials have been set up much more quickly than would have previously been possible, this does not mean that safety assessment has been compromised.

    In fact most of the vaccines being developed have now included tens of thousands of people in their trials, totalling nearly one quarter of a million people being involved in trials altogether. This is actually providing a larger amount of data than for many other vaccines routinely used (refer also to How are COVID-19 vaccines being tested?)

    Each country has its own processes for assessing and monitoring the safety of vaccines. In Australia, any COVID-19 vaccine must meet the same high standards of the TGA as any other vaccine. Vaccine safety remains the TGA’s top priority. COVID-19 vaccines will be prioritised, and more resources will be allocated to their assessment.

Questions about vaccine development

  • What types of vaccines are researchers developing?

    Researchers are using a variety of methods to develop COVID-19 vaccines, some of which are well established and some newer.

    Established technologies use either the whole virus or parts of the virus (usually proteins) to train the immune system to recognise it. These technologies include:

    • inactivated vaccines, where the whole virus is inactivated with chemicals or heat so that it cannot replicate
    • subunit vaccines, where only a component of the virus is used, such as a protein
    • live attenuated vaccines, which contain a weakened version of the virus. There are currently no live attenuated COVID-19 vaccines in clinical trials.

    Newer technologies used in the development of COVID-19 vaccines use the genetic code for a component of the SARS-CoV-2 virus, usually the spike protein or the part of it called the receptor binding domain. After vaccination, host cells take up the genetic code and manufacture that protein, which then triggers an immune response. These technologies include:

    • DNA and mRNA vaccines, which are molecules that contain genetic information (genes). These technologies have been under development for decades. However, there have not yet been any DNA or mRNA vaccines registered for use in humans.
    • Viral vector vaccines in which a chemically weakened harmless virus like a common cold adenovirus (the vector) is used to carry the genetic code for the spike protein from SARS-CoV-2. There are currently two licensed viral vector vaccines for humans, both for the Ebola virus. Viral vectors are also used in licensed gene therapy products.
  • How are COVID-19 vaccines being tested?

    Before a vaccine is registered for use, it is tested extensively during development and then in thousands of people. Testing first begins with laboratory research, then animal studies and finally human clinical trials.

    Clinical trials involve testing the vaccine in volunteers, and are conducted in phases:

    • Phase 1 clinical trials usually include a few dozen healthy adult volunteers and focus primarily on assessing safety, and also on demonstrating that the vaccine induces an immune response
    • Phase 2 clinical trials have hundreds of volunteers, and can include groups for whom the new vaccine is intended, for example, older adults, children or people with pre-existing medical conditions. These trials aim to show the vaccine induces an immune response and confirm that it is safe with acceptable side effects.
    • Phase 3 clinical trials include many thousands of participants and aim to show that a vaccine has efficacy (i.e. it is effective) in preventing people from getting the disease – in this case COVID-19. Phase 3 trials also thoroughly assess the vaccine for safety and side effects. In a phase 3 trial, researchers usually compare vaccinated people with people who received a placebo (like a salt water injection). They compare the rate of disease, disease severity and reported side effects between the two groups.

    For COVID-19 vaccines, some of these phases have been combined. For example, in phase 1/2 trials, results are analysed after the first few dozen volunteers are studied, then the trial proceeds in hundreds more. Also, some phase 3 studies have started once preliminary data from phase 1/2 trials are available. Having these ‘overlapping’ time frames has helped develop COVID-19 vaccines quickly and help make them available earlier to save lives.

  • Why are clinical trials sometimes paused and restarted?

    COVID-19 vaccine trials, in the same way as other vaccine clinical trials, are supervised by independent Data and Safety Monitoring Boards (also known as DSMBs). DSMBs can advise to pause or stop a trial if there are any safety events, such as a participant experiencing a severe illness or event that needs time to investigate more fully. This standard procedure is one of the important ‘checks and balances’ in clinical trials. Pausing a trial allows researchers to investigate the event and see if it may have been a side effect related to the vaccine or if it is coincidental. Since clinical trials usually include tens of thousands of participants and continue for many months, it is inevitable that some participants will experience unrelated illnesses during the trial.

    If researchers are concerned that the vaccine is causing unacceptable side effects, they can stop the trial. This has not yet happened for any COVID-19 vaccine trials.  

  • What is the process for getting a COVID-19 vaccine approved in Australia?

    The Therapeutic Goods Administration (TGA), part of the Australian Government Department of Health, is the organisation responsible for approving medicines and vaccines for use in Australia. Approved products are listed on the Australian Register of Therapeutic Goods. The TGA receives advice from an independent panel of experts on the Advisory Committee on Vaccines. The approval process involves a rigorous assessment of vaccine effectiveness and safety. Given the urgency of the pandemic, the TGA is prioritising COVID-19 vaccines via a faster pathway which involves the following steps:

    Provisional determination

    Being granted provisional determination means that a vaccine developer is eligible to proceed to apply for provisional registration from the TGA. It does not mean that provisional approval has been granted, but that the vaccine can be assessed by the TGA using the provisional registration pathway.

    As of 29 January 2021, the TGA had granted provisional determination to three companies for their COVID-19 vaccines:

    • AstraZeneca Pty Ltd, for the University of Oxford vaccine
    • Pfizer Australia Pty Ltd, for the Pfizer/BioNTech vaccine  
    • Janssen Cilag Pty Ltd, for the Janssen vaccine
    • Biocelect Pty Ltd (on behalf of Novavax Inc.), for the Novavax vaccine 

    Provisional approval

    The provisional approval pathway is a process that allows for temporary registration of promising new medicines and vaccines where the need for early access outweighs any potential risks. The decision to grant provisional registration is based on a number of factors, including:

    • the safety, quality and effectiveness of the vaccine has been satisfactorily established for its intended use
    • the sponsor’s plan to submit comprehensive clinical data before the provisional registration ends.

    After provisional approval, the TGA will continue to closely monitor any new data about the vaccine as it becomes available. Similar processes are used by regulatory authorities in other countries, such as the United States Food and Drug Authority and the European Medicines Agency.

    As of 29 January 2021, the TGA had granted provisional approval to one company for its COVID-19 vaccine:

    • Pfizer Australia Pty Ltd, for the Pfizer/BioNTech vaccine
  • Why are COVID-19 vaccines being developed so quickly?

    As of 29 January 2021, over 2.1 million people have died from COVID-19, and more than 14,000 are dying each day. In Australia, 909 people have died so far. Hundreds of millions of people are suffering from the ongoing social and economic devastation caused by the pandemic. The urgency of this crisis means that all available resources and efforts are being directed towards finding an effective vaccine.

    Developing and licensing a vaccine has in the past taken a decade or longer, but some COVID-19 vaccines have been registered and used within 12 months of the virus being discovered..

    Some of the reasons behind this rapid progress include:

    • Unprecedented funding and collaboration between vaccine developers and governments around the world. Financial risks have been taken, such as building manufacturing facilities before a vaccine is even available.
    • Technology has evolved to make vaccine development faster than in the past. Previously, viral vaccines could only be developed after growing the virus in a lab, which takes time. Newer technologies build vaccines using the genetic code for the virus, so researchers around the world were able to start their work as soon as the genome for the virus was released in January 2020.

    Clinical trials progress more quickly if a disease is widespread, as is the case with COVID-19 in many countries, as a significant difference between the unvaccinated and vaccinated groups can be detected sooner than for a rare disease.

  • Why was the University of Queensland COVID-19 vaccine abandoned?

    In a phase 1 trial this vaccine was found to trigger an immune response that may interfere with certain HIV diagnostic tests. The vaccine was based on the coronavirus spike protein. It also contained a protein fragment from the HIV virus, used to stabilise the spike protein. This protein fragment is harmless and cannot cause HIV or AIDS, but it can be recognised by the immune system, resulting in the production of antibodies against it.

    These antibodies were found to cause “false positive” results on HIV screening tests. This means the HIV screening test returned positive for participants who did not have HIV. This could cause confusion if people who received this vaccine needed to be screened for HIV at a later date. For this reason, the vaccine will not progress to phase 2/3 trials.

    It is common for some vaccines to fail during the development process, and this is partly why the Australian government secured advanced purchasing agreements with multiple vaccine developers.

Visit our COVID-19 vaccine development landscape page to understand the current state of development of COVID-19 vaccines and clinical trials.
Visit our COVID-19 vaccination program planning in Australia page to find the latest information about the COVID-19 vaccination program planning and vaccine rollout.