Australia’s trusted independent immunisation experts

We have provided answers to some of the most frequently asked questions about COVID-19 vaccines. We update this page regularly (last updated 27 July 2021).


NEW questions 

  • I am under 60 years of age, can I have the AstraZeneca vaccine and is it safe for me?

    On 13 July 2021 and 24 July 2021, the Australian Technical Advisory Group on Immunisation (ATAGI) issued statements on the use of COVID-19 vaccines in an outbreak setting, such as the current situation in Sydney where there is spread of COVID-19 in the community. 

    Currently in Australia, the supply of Pfizer vaccine is limited, while access to the AstraZeneca vaccine is relatively easier. The current COVID-19 outbreak includes the new Delta variant which is more infectious than other strains. When the virus is spreading in the community it is important that as many people as possible are vaccinated as quickly as possible. In outbreak settings, the benefits of vaccination are greater, and it is recommended that adults of all ages should strongly consider having the AstraZeneca vaccine. This includes adults aged < 60 years who cannot access the Pfizer vaccine. 

    As with any vaccine, you may have some temporary side effects after receiving a COVID-19 vaccine. Refer to What are the likely side effects from COVID-19 vaccines for more information. The AstraZeneca vaccine appears to be associated with a rare side effect called thrombosis with thrombocytopenia syndrome (TTS). If you experience any signs or symptoms consistent with TTS, you should seek immediate medical attention. See also What are the symptoms of thrombosis with rombocytopenia syndrome (TTS) for more information.

  • I had one dose of the AstraZeneca vaccine and am now pregnant. What is the advice for dose two?

    Women who received their first dose of the AstraZeneca vaccine and are pregnant can receive dose two of either the AstraZeneca vaccine or the Pfizer vaccine, although the Pfizer vaccine is preferred. Pregnant women should speak with their healthcare provider about the best choice for them. Providers and consumers may wish to consider:

    • there is a growing body of evidence supporting the safety of mRNA COVID-19 vaccines in pregnancy
    • there are still very limited data on the safety of viral vector vaccines (such as the AstraZeneca vaccine) in pregnancy
    • there are comparatively less data on the safety and efficacy of mixed vaccine schedules than completing the series with the same vaccine.
  • What is capillary leak syndrome? Can COVID-19 vaccine lead to capillary leak syndrome?

    Capillary leak syndrome is an extremely rare but severe relapsing-remitting condition where fluid from small blood vessels (capillaries) leaks into surrounding tissue.

    Cases of capillary leak syndrome after the AstraZeneca vaccine have been reported overseas. The TGA has received a report of one case of a patient who died from multi-organ failure but had signs of capillary leakage. It is not clear whether this was linked to the AstraZeneca vaccine as other causes could not be ruled out.

    The Pharmacovigilance Risk Assessment Committee (PRAC) in Europe is reviewing reports of capillary leak syndrome. At this stage, it is not yet clear whether the reports of capillary leak syndrome are linked to vaccination. 

  • Can I have a COVID-19 vaccine if I have a past history of capillary leak syndrome?

    A past history of the capillary leak syndrome is a contraindication to  the AstraZeneca vaccine. This means if you have had capillary leak syndrome in the past, you should have an alternative vaccine. 

  • What is myocarditis and pericarditis? Can the Pfizer vaccine lead to myocarditis and pericarditis?

    Myocarditis is inflammation of the heart muscle. Pericarditis is inflammation of the outer lining of the heart. Myopericarditis is where these two conditions occur together.

    A risk of myocarditis and pericarditis has been seen in people who have had mRNA COVID-19 vaccines (including the Pfizer vaccine) overseas, including in the USA, Israel and the UK. Cases have been reported more commonly in males aged <30 years, and mostly after the second dose. Most cases have been mild and these countries continue to recommend that the benefits of mRNA COVID-19 vaccine strongly outweigh the risk of myocarditis or pericarditis, as does the WHO GACVS.

    Cases of myocarditis and pericarditis after vaccination have also been reported in Australia. The TGA is monitoring these cases. Both these conditions occur relatively commonly in the general population, and not all cases that are reported after vaccination will be caused by the vaccine (i.e. some may occur coincidentally). 

    Myocarditis and pericarditis cases have also been reported after the AstraZeneca vaccine in the UK; however, these have not been reported more commonly than would be expected in the general population. 

  • Will a booster dose of COVID-19 vaccine be required?

    In Australia, additional or booster doses beyond the two-dose course of COVID-19 vaccine are not currently recommended.

    The need for any additional doses is being reviewed. See also “How long will protection from COVID-19 vaccines last?”

    Pfizer has initiated studies on booster and new variant vaccines.
    The CDC and FDA in the USA currently do not recommend a booster dose, as fully vaccinated people are protected against severe disease, including from variants like Delta. They will continue to monitor data and make recommendations on boosters when needed. 

    The Joint Committee on Vaccination and Immunisation (JCVI) in the UK has issued interim advice on what a booster program could look like. At this stage, the UK has not commenced a booster vaccination program for COVID-19 vaccines.

Questions about vaccination program

  • UPDATED - How many people in Australia have been vaccinated? 

    As of 24 July 2021, 11.1 million vaccine doses have been administered in Australia. Of those:

    • over 5.7 million doses were administered in the primary care setting (GP sites, GPRC sites, ACCHS)
    • over 500,000 doses were administered in aged and disability facilities
    • over 4.8 million doses were administered in state and territory clinics.

    The number of doses administered is updated regularly and is available on the Australian Government Department of Health website.

  • UPDATED - Which COVID-19 vaccines are currently being used in Australia?

    The COVID-19 vaccines currently in use are:

    • Comirnaty (Pfizer vaccine), an mRNA vaccine. The  Pfizer vaccine is registered for use in people aged 12 years and older, and is currently the preferred COVID-19 vaccine brand for use in people under 60 years of age. The Australian Government has procured 40 million doses of this vaccine.
    • COVID-19 Vaccine AstraZeneca (AstraZeneca vaccine), a viral vector vaccine. The AstraZeneca vaccine is registered for use in people aged 18 years and older. The Australian Government has procured 53.8 million doses of this vaccine; 3.8 million to be imported and 50 million to be manufactured in Australia.

    The Australia government also has an advanced purchase agreement with Spikevax (Moderna COVID-19 vaccine), a second mRNA vaccine. Moderna has been granted provisional determination for review by the TGA. Moderna can only start being used once registered by the TGA. The Australian Government has procured 25 million doses, with 10 million doses expected to arrive in September

    The Australian Government has a fourth advance purchasing agreement for 51 million doses 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 global COVAX Facility, which invests in COVID-19 vaccines and seeks to ensure they are distributed equitably across the world. 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.

  • UPDATED - Who can get a COVID-19 vaccine and how is the priority decided?

    Currently all people aged 40 years and older are eligible for COVID-19 vaccination. Some states and territories may amend who is eligible based on their COVID-19 situation as well as vaccine availability and they number of people choosing to be vaccinated. For example, the AstraZeneca vaccine is in more abundant supply and is available to adults aged <40 years. 

    There are other groups of people who are also eligible to receive the vaccine. As of July 23, the following groups are also available to be vaccinated:

    • All Aboriginal and Torres Strait Islander people aged 16 to 49
    • NDIS participants aged 16 years and over, and unpaid and informal carers of NDIS participants of any age
    • Temporary visa holders aged under 50 years who are currently in Australia and have been approved for return travel to Australia through the travel exemption process
    • Pregnant women
    • Quarantine and border workers
    • Healthcare workers
    • Aged care and disability care residents and staff
    • People aged 16 and over with an underlying medical condition or significant disability
    • Critical and high risk workers aged 16 and over including defence, police, fire, emergency services and meat processing.
    • Individuals with an Australian Border Force outwards travel exemption in an eligible category

    Adults aged 18-39 years can choose to receive the AstraZeneca vaccine if they cannot access the Pfizer vaccine as part of a priority group.

    Eligibility can be checked using the eligibility checker.

  • UPDATED - Where can people access the vaccine, and is it free?

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

    Some people can access the vaccine through their workplace (e.g. healthcare workers, residential aged care facility workers). Others can access the vaccine through general practices (that meet specific requirements), GP respiratory clinics, Aboriginal Controlled Community Health Services, pharmacies and state-run vaccination clinics.

    The National COVID Vaccine Taskforce is working with state and territory health departments to ensure national, broad coverage of primary care sites delivering the COVID-19 vaccine. More community pharmacies will be brought online as additional vaccine supply becomes available over the coming months. On 22 April 2021, the National Cabinet agreed that states and territories can choose to incorporate community pharmacies into their roll-out plans. Further details are available here

    Check with your state or territory for further information regarding pharmacy delivery of COVID-19 vaccines. As part of a pilot program, 22 pharmacies across regional and rural NSW began administering the AstraZeneca vaccine to over 60s from mid-July. Further details including participating pharmacies are listed on the NSW Health website.

  • Is the COVID-19 vaccine mandatory?

    On 28 June 2021, the National Cabinet announced that COVID-19 vaccination will now be mandatory for aged care workers and quarantine workers. 

    Residential aged care workers are mandated to have at least one dose by mid-September 2021 as a condition of working in a residential aged care facility.

    COVID-19 vaccination has also been mandated for all quarantine workers, including all workers directly and indirectly involved in managed quarantine facilities and those involved in the transport of quarantined individuals. State and territory governments will be responsible for addressing the mandated vaccination program for quarantine workers.

    For all other Australians, COVID-19 vaccination currently “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. 


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

    Herd immunity occurs when enough people in a population develop immunity, preferably from vaccination but also from natural infection, preventing the SARS-CoV-2 virus from easily spreading from person to person. 

    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 high level of long-term protection in most people and that prevents transmission of the infection between people. Vaccines that provide short-term protection require booster doses, making herd immunity harder to achieve. 

    Working out how many people in the population 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 to what extent herd immunity is being developed over time. 

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

    As of 24 July 2021, over 3.86 billion doses of a COVID-19 vaccine have been given to people worldwide, the most common vaccines used to date are:

    • AstraZeneca viral vector vaccine (180 countries)
    • Comirnaty (Pfizer), an mRNA vaccine (111 countries)
    • Moderna’s mRNA vaccine (62 countries)
    • Beijing/Sinopharm’s inactivated vaccine (64 countries)
    • Gamaleya’s viral vector vaccine (48 countries)
    • Sinovac’s inactivated vaccine (37 countries)
    • Janssen/Johnson & Johnson vaccine (33 countries)

    Several other vaccines have been approved and are being used in other countries. More information about vaccine doses administered globally can be found at the London School of Hygiene COVID-19 vaccine tracker and at Our World in Data.

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

    Australia still needs to keep the flexible and extensive strategies already in place to control COVID-19 during the rollout of the 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 as many people as possible being willing to have the vaccine.

  • How are COVID-19 vaccination encounters recorded?

    All vaccines given must be recorded on the Australian Immunisation Register (AIR). All immunisation providers must submit this information to AIR following the administration of the vaccine.  

    Individuals can view their vaccination history and download a statement using a Medicare online account accessed through myGov or the Express Plus Medicare mobile app. For those that can’t use Medicare online, vaccination providers can print the immunisation history statement or you can call AIR on 1800 653 809. 

Questions about getting vaccinated

  • UPDATED - 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. As of 23 July 2021, it has caused over 4 million deaths worldwide, with more than 192 million cases reported.

    Although the elderly and people with underlying medical conditions are at the highest risk, anyone, including healthy young people, can get severe disease and die of COVID-19. In some people, COVID-19 may cause long-term symptoms of fatigue and breathlessness. We are still learning about other long-term complications caused by COVID-19. The virus is also easily spread by people with few or no symptoms; even if you may not become unwell with COVID-19, you may pass the virus on to others without knowing it and they may become very ill.  

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

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

    Right now, people can’t choose which vaccine they are offered. Daily updates about the vaccine rollout are available at the Australian Government website.

    For people aged 16–60 years the preferentially recommended vaccine is the Pfizer vaccine. However, people in this younger age group can still choose to have the AstraZeneca vaccine now if they are unable to access the Pfizer vaccine, and if the benefits of vaccination outweigh the risk for them.

    With new outbreaks being caused by the more transmissible Delta variant and with limited supply of the Pfizer vaccine, ATAGI recommends people aged <60 years who do not have immediate access to the Pfizer vaccine should re-assess the need for vaccination with AstraZeneca vaccine. People aged <60 years in the Greater Sydney area should strongly consider taking the AstraZeneca vaccine if they can’t access the Pfizer vaccine. Refer to "I am under 60 years of age, can I have the AstraZeneca vaccine and is it safe for me" for more information.

    This section will be updated as further information becomes available.

  • 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. The genetic code is quickly broken down and cleared away by the body. 

  • 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 the genetic code for an important part of the SARS-CoV-2 virus called the spike protein that is carried into your cells by a harmless common cold ‘carrier’ virus (an adenovirus). Your body then makes and uses the spike protein to learn to recognise and fight against SARS-CoV-2. The carrier adenovirus has been modified so that it cannot spread to other cells and cause infection. For this reason, the AstraZeneca vaccine does not behave like a ‘live vaccine’.

  • UPDATED - How many doses of COVID-19 vaccine are required and what is the schedule?

    The number and timing of doses differs depending on the brand of COVID-19 vaccine used. COVID-19 vaccines are not considered interchangeable, and whenever possible, the two-dose schedule should be completed with the same vaccine.

    The AstraZeneca vaccine requires two doses, recommended to be given 12 weeks apart, because the efficacy of the vaccine is highest with this interval between doses. The minimum interval is 4 weeks if required in certain circumstances. On 13 July 2021, ATAGI specifically recommended that in the current Delta outbreak situation an interval of between 4 and 8 weeks is preferred. People living in outbreak areas, such as in Sydney, who received their first dose of COVID-19 Vaccine AstraZeneca more than 4 weeks ago should contact their vaccine provider to book their second dose as soon as possible. In non-outbreak settings, the preferred interval between doses of COVID-19 Vaccine AstraZeneca remains 12 weeks. 

    The Pfizer vaccine requires two doses, recommended to be given 3–6 weeks apart. 

    Administration of the Pfizer vaccine using a 6-week interval, rather than 3, provides strong protection at the individual level but also allows for more people to be vaccinated with the first dose earlier. 

    The ATAGI clinical guidance on COVID-19 Vaccine in Australia in 2021 has further details on dose timing.

  • What happens if the second dose is given late or is missed?

    If the second dose of either the Pfizer vaccine or the AstraZeneca vaccine is overdue (i.e. past the recommended interval), it should be given as soon as possible. A single dose likely only gives provide short-term protection. The second dose will be effective regardless of how late it is given. Even if the second dose is late, no vaccine doses need to be repeated.

  • 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 influenza vaccine, is not recommended. The preferred minimum interval between receipt of COVID-19 vaccine and any other vaccine is 7 days. This applies to all other vaccines, including live vaccines. A shorter interval (and even same day administration) is acceptable in special situations, such as in the context of an outbreak of COVID-19 or influenza, or after a tetanus-prone wound.

    Other, non-COVID-19 vaccines can be given either side of a COVID-19 vaccine dose if the interval is followed. It doesn’t matter which vaccine you receive first. Depending on vaccine availability, take whichever vaccine you have access to first.

    The COVID-19 vaccine program is not planned to impact on the 2021 influenza vaccine program. The influenza vaccine roll out is planned to continue as usual.

    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.

  • UPDATED - How effective are COVID-19 vaccines?

    In clinical trials COVID-19 vaccines have been shown to provide excellent protection from getting sick with COVID-19. In these trials, after two doses the Pfizer vaccine was about 95% effective and the AstraZeneca vaccine was at least 62–70% effective at preventing people from getting sick with COVID-19. 

    There are ‘real world' studies (also called observational or post-market vaccine effectiveness studies) from vaccination programs in countries like the USA, the UK and Israel that show strong protection for both vaccines.

    One such study in the UK showed that people who had received two doses of the Pfizer vaccine had 92% less symptomatic illness than those who had not been vaccinated. The vaccine was 72% effective in preventing all COVID-19 and 52% effective against milder COVID-19 where there were no symptoms. In the same study overall vaccine effectiveness was about 65% for both the Pfizer vaccine and the AstraZeneca vaccine from 21 days after the first dose.

    In an Israeli study, the Pfizer vaccine was 87% effective against COVID-19 requiring hospitalisations from 7 days after two doses.

    Information is available on COVID-19 vaccine effectiveness among older adults as they were prioritised for vaccination in many countries. In one UK study vaccine effectiveness against hospitalisation among adults 80 years and older from 14 days after dose 1 was 71% for theAstraZeneca vaccine and 79% for the Pfizer vaccine. In this study effectiveness of the first dose of either the Pfizer vaccine or the AstraZeneca vaccine was 76% against overall SARS-CoV-2 infection in people 75 years and older.

    Also, data from an observational study show that the minority who may develop SARS-CoV-2 infection despite vaccination is less likely to pass the virus on to their household contacts than those who are infected and are not vaccinated. This effectiveness against transmission from breakthrough infections was around 50% in people in the UK from 21 days after the first dose for both the Pfizer vaccine and the AstraZeneca vaccine.

    As new variants of the virus emerge, information on the effectiveness against these variants will become available – refer also to Will the COVID-19 vaccines be effective on new variants of the virus”

    Spikevax (Moderna) is an mRNA vaccine like the Pfizer vaccine. A study from the USA has found Spikevax to be 90% effective against hospitalisation from 14 days after dose 2. 

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

  • UPDATED - 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 how viruses affect us. However, some recent variants of SARS-CoV-2 are more easily spread and appear to be associated with increased numbers of cases in some countries.

    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 developed from vaccines based on the original strain can ‘neutralise’ the virus. 

    There have been four variants of concern (VoC) since the start of the global COVID-19 pandemic. The WHO has classified them as Alpha, Beta, Gamma and Delta. They also monitor Variants of Interest (VoI) and Alerts for Further Monitoring.

    Currently approved vaccines have been shown to be effective to provide at least some protection against new variants as these vaccines work to create a broad immune response. The mutations causing these variants should not make the vaccines ineffective. A study from the UK found the Pfizer vaccine is 96% effective against hospitalisation for the Delta strain after the second dose. This same study found AstraZeneca to be 92% effective against hospitalisation after two doses. 

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

    Pfizer has announced that Comrinaty provides immunity for at least 6 months. The Pfizer vaccine was found to be 91.3% effective against symptomatic COVID-19 up to 6 months after the second dose.

    As clinical trials and observational studies 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 COVID-19 vaccines will last. 

    A study from the UK found that 3 weeks after dose one, effectiveness of the Pfizer vaccine reached 72% and was maintained after that point. Another study from the UK found that 22–90 days after the first dose of AstraZeneca vaccine, the vaccine was 76% effective. They found that the amount of antibodies at day 90 fell by only a minimal amount. 

    More information on the duration of protection of COVID-19 vaccines will be available over the coming months.

  • UPDATED - Can different COVID-19 vaccines be mixed and matched?

    In Australia, both the Pfizer vaccine and the AstraZeneca vaccine require two doses of the same vaccine. This is because the evidence from clinical trials shows this is effective and is what is approved for use by the TGA. This advice may change over time.

    Many studies assessing the use of COVID-19 vaccines interchangeably are currently ongoing. Data have recently been released from two randomised controlled trials, the CombiVacS study in Spain and the Com-COV study in the UK, as well as a number of other studies around Europe.

    Participants in the CombiVacS study received the AstraZeneca vaccine followed by the Pfizer vaccine). The findings suggest having the Pfizer vaccine as a second dose induced a strong antibody response and the side effects were mild or moderate and short-lived.

    Participants in the Com-COV study received either the Pfizer vaccine first followed by the AstraZeneca vaccine or vice-versa. The findings showed both schedules induced an antibody response at least as high as receiving the AstraZeneca vaccine alone. In people who received mixed doses, side effects were mild or moderate and short-lived, but people who had a mixed schedule were more likely to report side effects than people who had the same vaccine for both doses.

    These studies are small, and more information is needed to confirm that mixed schedules are safe and effective before routinely recommending them for the general population.

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

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

    Some changes to the program are being made which will impact who is offered which vaccine, where and when. Be sure to check the Australian Government COVID-19 vaccine program website for any updates.

    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?

    COVID-19 vaccines are available to adults, even people with a history of SARS-CoV-2 infection. 

    The vaccine clinical trials included some previously infected people (who had a blood test showing past infection). These people had a good immune response to the vaccine 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 for up to 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. 

    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 up to 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 for 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 guides  for a list of common side effects noted after each vaccine and what to do in the event of a side effect.

  • UPDATED - Can children have a COVID-19 vaccine?

    On 23 July 2021, the TGA provisionally approved the use of the Pfizer vaccine in people aged 12 years and older. Previously, the Pfizer vaccine was provisionally approved for use in people aged 16 years and older. Children and adolescents aged <18 years cannot have the AstraZeneca vaccine.

    On 31 March 2021, Pfizer announced results of a study in adolescents aged 12–15 years vaccinated with the Pfizer vaccine. The study showed the Pfizer vaccine efficacy of 100% and was considered safe in this age group.

    In the US children aged 12 years and older can receive the Pfizer vaccine. As of 25 July 2021, 27.7% of the children aged 12–15 years were fully vaccinated and 37% had received at least one dose in the US.

    ATAGI is reviewing the evidence on the safety and efficacy of the Pfizer vaccine in this age group and is in the process of developing updated recommendations. These will be made available shortly. 

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

    Yes, the Pfizer vaccine is now routinely recommended for pregnant women. This is a joint recommendation from the Australian Immunisation Technical Advisory Group and the Royal Australian and New Zealand College of Obstetricians and Gynaecologists. The Pfizer vaccine continues to be recommended for breastfeeding women and women planning pregnancy. 

    Research has shown that pregnant women have a higher risk of severe illness from COVID-19, and compared with non-pregnant women with COVID-19 they are more likely to need admission to an intensive care unit and mechanical ventilation. They are also more likely to deliver their babies early, and their babies are more likely to require admission to a newborn intensive care unit. 

    There is now real-world evidence from countries such as the USA showing that mRNA COVID-19 vaccines (such as the Pfizer vaccine) are safe in pregnant women, and the side effects they report are similar to those in non-pregnant women. 

    If the Pfizer vaccine is not available, the AstraZeneca vaccine can be given to pregnant women if the benefits of vaccination outweigh the risks for the individual. 

    Women who are breastfeeding don’t need to stop breastfeeding after vaccination. Women who are planning pregnancy don’t need to avoid becoming pregnant after vaccination. 

    Women who received their first dose of the AstraZeneca vaccine and are pregnant can receive dose two of either the AstraZeneca vaccine or the Pfizer vaccine, although the Pfizer vaccine is preferred. See also “I had dose one of the AstraZeneca vaccine and am now pregnant. What is the advice for dose 2”.

    More information is available in 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 – the Pfizer vaccine or the AstraZeneca vaccine. 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. 

    The Pfizer vaccine is not a live vaccine. The AstraZeneca vaccine 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.

    If you are taking an immune-weakening treatment (immunosuppressant/immunomodulator), including chemotherapy, you should discuss the best timing of vaccination with your treating doctor. 

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

    Almost all people with allergies can have a COVID-19 vaccine. This includes people with food allergies, asthma or hayfever. 

    People who have had anaphylaxis (a type of severe allergic reaction) to a particular COVID-19 vaccine, or to an ingredient of a COVID-19 vaccine, should not have another dose of that vaccine. They may be able to have an alternative brand of COVID-19 vaccine.

    For some people, precautions may be needed before vaccination, such as consulting an allergy specialist, being vaccinated in a facility which has medical staff and being observed for at least 30 minutes after vaccination.

    This applies to people in the following groups:

    • people who have had a suspected allergic reaction after a dose of a COVID-19 vaccine 
    • people who have had an allergic reaction (but not anaphylaxis) to an ingredient of a COVID-19 vaccine
    • people who have had anaphylaxis to other vaccines or to medications (including injectable or oral medications) where there may be common ingredients with a COVID-19 vaccine (such as polyethylene glycol, an ingredient in Comirnaty, or polysorbate 80, an ingredient in COVID-19 Vaccine AstraZeneca) 
    • people who have a mast cell activation disorder.
  • 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, or to one of its ingredients, 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.

  • UPDATED - Can I have a COVID-19 vaccine if I have a history of Guillain-Barre Syndrome?

    Yes, if you have a past history of GBS, you can have a COVID-19 vaccine. There have been cases of GBS following vaccination in Australia and overseas. The European Medicines Agency (EMA), the US Advisory Committee on Immunisation Practices (ACIP) and the World Health Organisation Global Advisory Committee on Vaccine Safety (GACVS) have reviewed cases of GBS following COVID-19 vaccination. At this stage, it is not yet clear whether the reports of GBS are linked to vaccination. GACVS recommended that individuals receiving COVID-19 Vaccine AstraZeneca or Janssen should seek immediate medical attention if they develop signs and symptoms of GBS. Symptoms may include difficulty in walking; difficulty with facial movements; double vision or inability to move eyes; or difficulty controlling bladder or bowel functions.

  • What is Bell’s palsy? Can COVID-19 vaccines lead to Bell’s palsy?

    Bell’s palsy causes paralysis (weakness) of one side of the face. The exact cause is not known, but it is thought to often be triggered by a recent viral illness. It is treatable, and most cases resolve fully.

    The evidence to date does not support an association between COVID-19 vaccines and Bell’s palsy. However, cases of Bell’s palsy have been reported after COVID-19 vaccines. There were 4 cases of Bell’s palsy in the group of >18,000 participants who received the Pfizer vaccine in the phase 3 clinical trial, and there were no cases in the group who received the placebo. Cases of Bell’s palsy have also been reported after COVID-19 vaccines in several countries. 

    It is not yet known whether these reported cases are coincidental, because they have not been reported at a higher rate than what would be expected in the general population. 

  • Can I have a COVID-19 vaccine if I have a past history of Bell’s palsy?

    Yes, if you have a past history of Bell’s palsy, you are recommended to have a COVID-19 vaccine. 

    The evidence to date does not suggest that COVID-19 vaccines can trigger Bell’s palsy. 

  • UPDATED - Does the AstraZeneca vaccine lead to blood clots?

    Yes, but very rarely. The AstraZeneca vaccine is associated with a very rare risk of a condition called thrombosis with thrombocytopenia syndrome, or TTS.

    TTS involves blood clots (thrombosis) along with low blood platelet levels (thrombocytopenia), and occurs around 4-28 days after vaccination. As at 8 July it is estimated to affect estimated to affect around 2 per 100,000 doses in Australia. To date, the great majority of cases were after the first dose of the vaccine. 

    The Pfizer vaccine is not associated with a risk of TTS. 

    Not all clots that occur after having the AstraZeneca vaccine will be due to TTS. Other blood clotting problems occur commonly in the population. Annually, common clots such as deep vein thrombosis or pulmonary embolism (a clot in the lungs) will affect about 1 in a 1,000 people in Australia, unrelated to any vaccine.

    TTS is a unique, new condition that requires certain blood tests to confirm it. 

  • UPDATED - Who is at risk of getting thrombosis with thrombocytopenia syndrome (TTS)?

    Younger adults (i.e. under 60 years of age) appear to have a higher risk of thrombosis with thrombocytopenia syndrome (TTS) than older adults. No other specific factors (such as pre-existing medical conditions) have been linked to, or found to predict, the likelihood of this condition occurring. 

    More cases of TTS have been reported in women, but it is not yet clear if sex is a risk factor. More women than men have been vaccinated in many of the countries using COVID-19 Vaccine AstraZeneca, since women make up a large proportion of frontline healthcare workers and who have been prioritised for vaccination.

  • If I have a history of blood clots or an increased risk of clotting, can I still have the AstraZeneca vaccine?

    Most people who have had blood clots in the past, or who have an increased risk of blood clots, can still have COVID-19 Vaccine AstraZeneca. This is because the vaccine does not increase the overall risk of blood clots. People with a history of the following conditions can receive the AstraZeneca vaccine:

    • deep vein thrombosis or DVT (a type of blood clot usually in the leg or arm)
    • pulmonary embolism (a type of blood clot in the lungs)
    • stroke
    • heart attack
    • a family history of blood clots
    • current or past thrombocytopenia (low platelet count)
    • those taking an anticoagulant medication 

    These conditions do not increase the risk of TTS. 

    If you have an increased clotting tendency, talk to your doctor before having the AstraZeneca vaccine. The AstraZeneca vaccine is safe for people with clotting tendencies that are not immune-mediated. This includes conditions such as Factor V Leiden. 

    If you have had one of the following rare, specific causes of blood clots, you are recommended to have the Pfizer vaccine instead of the AstraZeneca vaccine:

    • a clot in a blood vessel in the brain, called cerebral venous sinus thrombosis 
    • a type of blood clot in the abdomen (i.e. in the splanchnic circulation, which includes the mesenteric, portal or splenic veins), without any other known cause (i.e. idiopathic)
    • a condition called ‘heparin induced thrombocytopenia’, which is a reaction to the medicine heparin
    • a blood clot associated with antiphospholipid syndrome.

    There is a theoretical concern that the above conditions may increase the risk of TTS. 

  • UPDATED - Why is the Pfizer vaccine now preferred for people under 60 years of age?

    The Pfizer vaccine is recommended as the preferred vaccine over the AstraZeneca vaccine for people under 60 years of age based on an assessment of benefits and risks. While thrombosis with thrombocytopenia syndrome (TTS) is very rare overall, it appears to be more common in younger adults than in older adults.

    For adults over 60 years of age, the benefits of vaccination with the AstraZeneca vaccine greatly outweigh the risks because this age group has a lower risk of TTS but have a higher risk of severe disease and death from COVID-19.

    In outbreak areas, such as the current outbreak in Greater Sydney, the benefits of vaccination with the AstraZeneca vaccine are greater than the risk for all people, including people under 60 years of age. 

    Similarly, the risk-benefit balance will be different for different countries, depending on their local rates of COVID-19.

    People under 60 years of age can still choose to have the AstraZeneca vaccine if the benefits of vaccination clearly outweigh the risk for them personally and they provide informed consent. 

    For further information on weighing up the risks and benefits refer to COVID-19 vaccination – Weighing up the potential benefits against risk of harm from COVID-19 Vaccine AstraZeneca document. 

  • UPDATED - Why should we still use the AstraZeneca vaccine now that we know about thrombosis with thrombocytopenia syndrome (TTS)?

    All medicines and vaccines can be associated with rare side effects. We have to balance the potential risk of a serious side effect with the benefits of each medicine or vaccine we take. 

    There is an ongoing threat of COVID-19 in Australia and a clear need to have as many people living in Australia vaccinated as practical. Vaccination helps both individuals and the community to be protected.

    We also will not be able to avoid restrictions, begin to open borders, have Australians return home or return to a more usual way of life until a great portion of our community is vaccinated. 

    The AstraZeneca vaccine is the most widely available vaccine in Australia at the current time and is recommended for people age 60 years and older.

    The Pfizer vaccine is preferred for adults under the age of 60 years. In outbreak settings, people 60 years and younger who do not have immediate access to the Pfizer vaccine should strongly consider vaccination with the AstraZeneca vaccine.

  • Where can providers find information about thrombosis with thrombocytopenia syndrome (TTS)?
  • What are the symptoms of thrombosis with thrombocytopenia syndrome (TTS)?

    The symptoms of thrombosis with thrombocytopenia syndrome (TTS) can vary depending on the location and extent of the blood clot. Possible symptoms include:

    • severe, new and persistent headache which is not getting better with simple painkillers
    • vomiting, and may be worse when lying down
    • blurred vision, seizures, difficulty speaking or drowsiness
    • new chest pain or difficulty breathing
    • abdominal pain associated with feeling unwell
    • tiny blood spots under the skin 

    The symptoms are most likely to appear between 4 and 28 days after vaccination with COVID-19 Vaccine AstraZeneca. TTS can cause serious illness, disability or even death. Anyone who has concerning symptoms after vaccination, such as those listed above, should seek medical care urgently. 

    For further information, read the Department of Health’s patient information sheet on AstraZeneca vaccine and thrombosis with thrombocytopenia syndrome.

  • Is thrombosis with thrombocytopenia syndrome (TTS) curable? 

    Thrombosis with thrombocytopenia syndrome (TTS) is a newly discovered but rare condition that can occur rarely at around 4-42 days after vaccination with COVID-19 Vaccine AstraZeneca. Specialists have already developed specific ways to treat it, including treatments such as anticoagulant medication (other than heparin), intravenous immunoglobulin (an antibody infusion) and prednisolone (a steroid). 

    Of the TTS cases reported in the UK, about 80% of people who had TTS survived, and 19% unfortunately died. Now that doctors are better able to recognise and treat TTS early, it is hoped that the survival rate will improve. 

    Of note, some of the recent cases of TTS reported to the TGA that have been linked to the AstraZeneca vaccine have been milder than those first recognised.

  • Are there any medications known to increase the risk of thrombosis with thrombocytopenia syndrome (TTS)?

    No, it is not yet known whether any medications increase the risk of thrombosis with thrombocytopenia syndrome (TTS). This includes medications such as aspirin and other anti-platelet drugs, heparin or low molecular weight heparin. There are no specific theoretical safety concerns for these drugs. 

    There are three published case series (1, 2, 3) of patients who had TTS after AstraZeneca vaccine, and in both case series, no patient had a history of exposure to heparin. 

  • UPDATED - If I’ve already had my first dose of AstraZeneca vaccine, can I still have the second dose?

    Thrombosis with thrombocytopenia syndrome (TTS) has predominantly been reported after a first dose of the AstraZeneca vaccine. The risk is much lower after the second dose. In the UK, 44 cases of TTS have been reported out of the 22.8 million second doses given of the AstraZeneca vaccine.

    People who have had their first dose of the AstraZeneca vaccine without any serious side effects can have the second dose. This includes people under 60 years of age.

    Women who received their first dose of COVID-19 Vaccine AstraZeneca and are pregnant can receive dose two of either the AstraZeneca vaccine or the Pfizer vaccine, although the Pfizer vaccine is preferred.

    People who have had their first dose of the AstraZeneca vaccine and are subsequently found to have had a past history of heparin-induced thrombocytopenia (HIT), cerebral venous sinus thrombosis (CVST), splanchnic (mesenteric, splenic, portal) thrombosis or antiphospholipid syndrome with thrombosis are recommended to receive the Pfizer vaccine for their second dose. 

    People who have had a blood clot associated with low platelet counts after their first dose of the AstraZeneca vaccine should not have the second dose. If you’re unsure about the second dose, talk to your healthcare provider to help you weigh up the risks and benefits.

  • Can I take heparin if I’ve had the AstraZeneca vaccine?

    Yes, there is no evidence that exposure to heparin increases the risk of TTS.

  • Can I have the AstraZeneca vaccine if I’ve recently been given heparin?

    Yes, there is no evidence that exposure to heparin increases the risk of TTS.

  • If I’ve had a blood clot recently, how long should I wait before having the AstraZeneca vaccine?

    It’s recommended to wait around a week, particularly if you’ve been started on anticoagulation treatment, just to make sure your treatment is stable. As for any other vaccine, vaccination should be deferred until you feel well and have recovered from any acute illness. 

  • Could the vaccine react with other medications? Do other medications need to be stopped to have a COVID-19 vaccine?

    No, in most cases medication should not be stopped before having a vaccine. There are a few situations in which people might be advised to either delay vaccination or delay a particular medication:

    • Some people taking blood thinners (anticoagulants) may be advised to delay vaccination if there is a high risk of bleeding after the vaccine is injected. Most people on a stable dose of blood thinner will be able to receive the vaccine without any change to their medication.
    • People taking immune-weakening treatments (immunosuppressants), including chemotherapy, should discuss the best timing of vaccination with their treating doctor. 

    People taking other medications should continue their regular treatment before and after vaccination. 

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). They do not contain any live SARS-CoV-2 virus. 

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

    All vaccines can cause side effects. Usually these are mild and temporary. 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 and go away without treatment.  

    The most common side effects for both vaccines include pain at the injection site, tiredness, headache, muscle pain, chills, joint pain and fever. These side effects are temporary and go away without treatment in 1–2 days. Sometimes these flu-like side effects can mean people don’t carry out their usual activities for a day or so. 

    For more detailed information about the side effects of each vaccine, refer to:

    AusVaxSafety is actively monitoring the side effects reported after COVID-19 vaccines in Australia. The surveillance data report is updated weekly.

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

    Common side effects include pain, redness or swelling at the site of your injection, as well as tiredness, headache or fever. You can take paracetamol or ibuprofen to help with side effects like pain, headache or fever. 

    These short-term side effects are expected and reflect a developing immune response to vaccination. If you have significant side effects (such as fever, tiredness or muscle aches) which are preventing you from carrying out your usual activities, you may need to take extra rest until you feel better. 

    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. 

    Be aware of the very rare possibility of serious symptoms after AstraZeneca vaccine caused by TTS. These symptoms may include new onset severe headache or abdominal pain starting in the 4-42 days after vaccination. Be sure to seek medical attention if you have any concerns (see also the question above What are the symptoms of thrombosis with thrombocytopenia syndrome (TTS)?)

    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.

  • If I have side effects after the first dose of a COVID-19 vaccine, can I still have the second dose?

    Yes, almost always. Side effects such as pain at the injection site, fever, chills, tiredness, headache and muscle aches occur commonly after the first dose of a COVID-19. You should have the second dose even if you experienced these side effects.

    These side effects are caused by your immune system responding appropriately to the vaccine. Although they cause discomfort and inconvenience, they are usually brief and go away within a few days. Some people may need to take paracetamol or ibuprofen to help reduce the discomfort. You may also need to take extra rest in the day or so after vaccination, until you feel better.

    Having the second dose is important to ensure you get the best possible protection against COVID-19.  

    If you have had a severe allergic reaction to your first dose, or any other severe symptoms that you are worried about or have been diagnosed with TTS after the AstraZeneca vaccine, discuss these with your healthcare provider before having the second dose.

  • How can I report a potential side effect after immunisation?

    If you have any side effects that are unexpected, severe, or which you are concerned about, you can report them 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. 

    For information on how to make the report, refer to the TGA webpage Reporting suspected side effects associated with a COVID-19 vaccine

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

    Both the Pfizer vaccine and the AstraZeneca 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.

  • Do COVID-19 vaccines used in Australia contain material from aborted fetuses?

    There are no cells from aborted tissue in any COVID-19 vaccine. During the development of the AstraZeneca vaccine, cells were used that were derived from a fetus aborted in the 1970s. The abortion was elective, and was not done for the purpose of research. Fetal cell lines were not used in the development or manufacturing of the Pfizer vaccine, but they were used during the testing stages of the vaccine. 

  • Is the mRNA in some COVID-19 vaccines harmful?

    Some COVID-19 vaccines, including the Pfizer vaccine, contain mRNA, a form of genetic code. This mRNA contains the code for an important part of the SARS-CoV-2 virus called the ‘spike protein’. After vaccination, our cells make some copies of the spike protein, and this trains our immune system to recognise and fight against SARS-CoV-2. mRNA is very fragile and gets broken down and removed very quickly and easily by our body. 

    mRNA vaccines such as the Pfizer vaccine and the Moderna vaccine have been given to tens of millions of people around the world, and have been safe and well tolerated. 

    The only serious side effect that has been confirmed to be caused by an mRNA vaccine is anaphylaxis, a type of serious allergic reaction, which can occur after any vaccine or medicine, and which is treatable.

    Anaphylaxis after an mRNA vaccine is still very rare. The rate of anaphylaxis after the Pfizer vaccine in the USA as of February 2021 was 4.7 cases per million people. 

  • Does the AstraZeneca vaccine contain a live virus?

    No. The AstraZeneca vaccine contains a harmless ‘common cold’ virus (an adenovirus) that carries the piece of genetic code for the SARS-CoV-2 spike protein into your cells. This adenovirus has been modified so that it can only enter your cells once, and it cannot replicate and spread to other cells. It therefore cannot cause infection, and does not behave like a ‘live vaccine’. It is considered safe for people who cannot have live vaccines, such as people with immunocompromise (weakened immune systems). 

  • 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.

    Safety monitoring allows us to pick up rare unexpected side effects and adjust vaccine program recommendations and information, as has occurred recently in Australia. 

  • 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.

    Weekly TGA reports on COVID-19 vaccine safety monitoring are published here.

    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, and safety monitoring data are published weekly here.

    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.

Questions about vaccine development

  • What types of vaccines have researchers developed?

    Researchers have used and 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 have COVID-19 vaccines been 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 four 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 

    As at April 2021, TGA has not granted provisional determination to any other company.

    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 4 March 2021, the TGA has granted provisional approval to two companies for their COVID-19 vaccines:

    • Pfizer Australia Pty Ltd, for Comirnaty
    • AstraZeneca Pty Ltd, for COVID-19 Vaccine AstraZeneca 
  • Why are COVID-19 vaccines being developed so quickly?

    As of 9 July 2021, more than 4 million people have died from COVID-19 globally, and more are dying each day. In Australia, 911 people have died and approximately 31,103 people have been infected. 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 have been directed towards finding effective vaccines.

    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.

Visit our COVID-19 vaccination program in Australia page to find the latest information and resources on the COVID-19 vaccination program, ATAGI statements and more.
Visit our COVID-19 vaccine development landscape page to understand the current state of development of COVID-19 vaccines and clinical trials.