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COVID-19 vaccine weekly safety report - 08-07-2021

Vaccination against COVID-19 is the single most effective way to reduce severe illness and death from infection. Two COVID-19 vaccines are currently in use in Australia – AstraZeneca and Comirnaty (Pfizer). Like all medicines, the vaccines can have side effects (also known as adverse events). The overwhelming majority of these are mild and resolve within a few days. The Therapeutic Goods Administration (TGA) closely monitors suspected side effects. Importantly, adverse events reported to the TGA are often not caused by the vaccine itself. Learn more about causality.

Learn about the TGA’s COVID-19 vaccine safety monitoring and reporting activities or report a suspected side effect.


  • The most frequently reported suspected side effects associated with Comirnaty (Pfizer) and AstraZeneca COVID-19 vaccines continue to be events that were seen in the clinical trials, and are commonly experienced with vaccines generally.

  • An external Vaccine Safety Investigation Group (VSIG), convened by the TGA on 2 July 2021, concluded that a very rare but fatal case of immune thrombocytopenia (ITP)  in a 61-year-old woman who had received the AstraZeneca vaccine was likely to be related to immunisation.

  • Seven additional cases of blood clots with low blood platelets have been assessed as thrombosis with thrombocytopenia syndrome (TTS) likely to be linked to the AstraZeneca vaccine. When assessed using the United Kingdom (UK) case definition, three were confirmed TTS and four were deemed probable TTS. This brings the total number of cases of TTS to 76 out of five million doses to date.

Reported side effects for COVID-19 vaccines

Gathering reports of adverse events following immunisation (AEFI) is just the first step in determining whether or not the effect is related to the vaccine and whether a significant safety issue is involved. Learn more about how the TGA identifies and responds to safety issues

In the week of 28 June - 4 July 2021 we received 1,646 AEFI reports for COVID-19 vaccines. 

Large scale vaccination means that coincidentally some people will experience a new illness or die shortly after vaccination. The TGA reviews all deaths reported in people who have received the vaccination. We also monitor signals that may relate to vaccine safety to distinguish between coincidental events and possible side effects of the vaccine. Part of our analysis includes comparing natural expected death rates with observed death rates following immunisation. So far, the observed number of deaths reported after vaccination remains less than the expected number of deaths that would occur naturally, or from other causes, for that proportion of the population. 

Since the beginning of the vaccine rollout to 4 July 2021, over 8.2 million doses of COVID-19 vaccines have been given. The TGA has received and reviewed 355 reports of deaths in people who have recently been vaccinated and found that only three were linked to immunisation. These deaths were all related to the first dose of the AstraZeneca vaccine – two were TTS cases and one was a case of ITP (reported below).

Total adverse event reports to 4 July 2021

Reporting rate per 1000 doses
Total AEFI reports received
Total doses administered
Total reports for AZ vaccine
Total reports for Comirnaty
Total reports for brand not specified

Reporting rates per 1000 doses by jurisdiction

Australian Capital Territory
New South Wales
Northern Territory
South Australia
Western Australia

Most commonly reported vaccine side effects

The most common adverse effects following immunisation  reported to the TGA are predictable and have been observed with vaccines generally. They include headache, muscle pain, fever, chills, nausea and injection site reactions.

The most common reactions reported for the AstraZeneca vaccine in the week 28 June – 4 July 2021 were headache, fatigue, muscle pain, fever and nausea.

The most common reactions reported for the Comirnaty (Pfizer) vaccine in the week of 28 June – 4 July 2021 were headache, muscle pain, lethargy, fever and nausea.

Interpreting information on vaccine adverse event reports

We are aware that false claims are circulating based on misinterpretation of adverse event information published by medicine regulators. To improve transparency, the TGA makes adverse event reports publicly available in the Database of Adverse Event Notifications (DAEN). Similar information is published by other regulators overseas. When interpreting this information, it is important to understand that many of these events may not be caused by vaccine. 

The TGA encourages reporting of adverse events even if people are uncertain or only suspicious that it is related to a vaccine or medicine. This supports our scientists and health professionals to use the data to look for new safety signals. Reporting of adverse events, such as the death of anyone who has received a vaccine, is mandatory for health professionals in some states, even if they know it is unrelated to immunisation. It is therefore important to remember that the number of adverse events and deaths is not an indicator of the safety of the vaccines. Detailed investigation and expert review of this data and individual cases are required to assess whether there is a link between an event and the vaccine. 

It is important when looking for information about COVID-19 vaccines to consider whether the source of the information is credible. Useful websites such as ‘COVID vaccines – is it true?’ help to debunk false claims and misleading rumours. Other reliable resources are listed at the end of this report.

AstraZeneca COVID-19 vaccine

We continue to receive reports of side effects to the AstraZeneca vaccine. The reports are generally consistent with what is being observed internationally and most are expected side effects that we know occur after vaccination and resolve within a few days. So far, approximately five million doses of the AstraZeneca have been administered.

Immune thrombocytopenia (ITP)

The TGA is closely monitoring reports of ITP in light of a case in a 61-year-old woman from Western Australia who developed severe ITP after receiving the AstraZeneca vaccine. Sadly the woman died and we extend our sincerest condolences to her family and loved ones.

An external Vaccine Safety Investigation Group (VSIG) of clinical experts and consumer representatives, convened on 2 July 2021, concluded that the woman’s death was likely linked to the vaccine. This was based on the lack of strong evidence for other causes and the occurrence of the event being within a plausible time period after vaccination. While the woman had experienced a recent viral illness that could have theoretically caused ITP, the panel felt that the unusual severity of the event suggested that vaccination was a more likely cause.

ITP is a rare bleeding disorder that occurs when the immune system mistakenly destroys platelets, which help blood to clot. It can occur after the immune system is activated, for example by a viral infection or vaccination, and has been reported with other vaccines for hepatitis B, measles, mumps, rubella and influenza. Up to a third of people with ITP will have no symptoms at all, or have only minor bruising. However, about 5% develop severe bleeding. 

The risk of ITP associated with the AstraZeneca vaccine is still being investigated and characterised. Preliminary findings from a recent Scottish study estimate the risk of ITP to be about 1 case per 100,000 AstraZeneca doses. To 4 July 2021, the TGA has received 36 reports of suspected ITP. The TGA continues to investigate this issue and we will report more information when it is known.

We encourage people to seek medical attention if they experience signs and symptoms that could suggest ITP, such as unusual skin bruising or clusters of small red or purple spots that do not lose their colour when pressed. Unusual bleeding is another sign, for example bleeding from the nose or mouth that is hard to stop, or blood in the urine or stools.

Thrombosis with thrombocytopenia syndrome (TTS)

The TGA and other international medicines regulators continue to closely monitor and investigate TTS. This is a rare event involving serious blood clots with a low blood platelet count. It is triggered by the immune system’s response to the AstraZeneca vaccine and is different from other clotting conditions. Updated reporting rates of TTS in Australia were published in a statement from Australian Technical Advisory Group on Immunisation (ATAGI) on 1 July 2021.

While Pfizer’s Comirnaty vaccine is preferred over the AstraZeneca vaccine for those aged 16–60 years old, as recommended by ATAGI, the AstraZeneca vaccine remains approved by the TGA (and most other major regulators) for those aged 18 and over.

Information is available to help people weigh up the benefits and risks of receiving the AstraZeneca vaccine. While TTS is very rare, some people may have concerns that they can discuss with their doctor. This is essential to allow people to make an informed choice about vaccination. 

People should seek immediate medical attention if they develop any of the following symptoms after vaccination:

  • severe or persistent headache or blurred vision

  • shortness of breath, chest pain, leg swelling or persistent abdominal pain

  • unusual skin bruising and/or pinpoint round spots beyond the site of vaccination.

The most common time period for onset of TTS symptoms is 4–30 days after vaccination.

VSIG review of possible TTS following a second dose of the AstraZeneca vaccine

The VSIG held on 2 July also reviewed a case of a 73-year-old man with possible TTS following his second dose of the AstraZeneca vaccine. On further investigation, the panel concluded that the case was unlikely to be related to vaccination as the patient had a very mild and transient form of thrombocytopenia, a common clot in the leg and he did not have anti-PF4 antibodies. In addition, the patient had an underlying condition known to increase the risk of blood clots.

To date, there have been no confirmed or probable case of TTS in Australia that occurred after the second AstraZeneca dose. People under 60 years of age who have already received their first AstraZeneca dose should complete the two-dose schedule as the risk of TTS after the second dose is extremely low (1.6 cases per million second doses based on UK data).

TTS cases to date

Since last week’s report, a further seven reports of blood clots and low blood platelets have been assessed as confirmed or probable TTS likely to be linked to the AstraZeneca vaccine (Table 1).  

Table 1: Newly confirmed and probable TTS cases for the week of 25 June-1 July 2021‡

New confirmed TTS

New probable TTS

Three new cases:

  • 59-year-old woman and a 59-year-old man from Victoria

  • 72-year-old woman from South Australia

Four new cases:

  • 60 and 68-year-old women and a 71-year-old man from NSW

  • 82-year-old woman from Western Australia

As previously reported, the TGA determines whether a report is likely to represent TTS by assessing cases against a consistent set of criteria, based on the case definitions established by the UK’s Medicines and Healthcare products Regulatory Agency.

In addition to the new cases identified above, one previously reported case was reclassified from probable to confirmed. This takes the total Australian reports assessed as TTS following the AstraZeneca vaccine to 45 confirmed cases and 31 probable cases, with a total of 76 cases overall from approximately five million doses of the AstraZeneca vaccine. 

When assessed against the criteria used by the US Centers for Disease Control and Prevention (CDC), fewer than half of the cases reported to TGA are classified as Tier 1 cases which tend to have more serious outcomes. Tier 1 cases involve clots in an unusual location, such as the brain or abdomen (Table 2). The Tier 2 and unclassified TTS cases had only the more common clots like deep vein thrombosis or pulmonary embolism.   

Table 2: Total confirmed and probable TTS cases to date by age and CDC classification


Total cases

CDC classification†

Tier 1

Tier 2

Not classified

<30 years



































All ages


(36 men, 40 women)




† The US CDC classification is defined as:

  • Tier 1 = clots in an unusual location (such as the brain or abdomen) and a low platelet count with or without antibodies that activate platelets (anti-PF4 antibodies)

  • Tier 2 = clots found in common locations (such as the leg or lungs) and a low platelet count and anti-PF4 antibodies

  • Not classified = case does not meet the criteria for Tier 1 or Tier 2 (for example clots in common locations with low platelet count but no evidence of anti-PF4 antibodies).

Cases have most often occurred about two weeks after vaccination, although the time to onset (or diagnosis) has ranged from one to 54 days (Table 3). In some cases with a longer time to diagnosis, patients had experienced symptoms at an earlier stage but complicating factors, including symptoms from comorbidities, may have delayed a clear diagnosis. A little over one in four TTS cases has required Intensive Care Unit (ICU) treatment, although all but six patients have since been released from ICU. 

Table 3: Time to onset, treatment and outcomes for TTS cases*

Time to onset/ diagnosis (days)

Median (range)

12 (1-54)

Treated in ICU

At any point







In hospital 




*Data is based on the most recent medical information available to the TGA

Guillain-Barre Syndrome (GBS)

The TGA has been closely monitoring reports of GBS since the beginning of the COVID-19 vaccine rollout as GBS has been associated with other types immunisations such as influenza vaccines. To 4 July 2021, the TGA has received 52 reports of suspected GBS following vaccination with the AstraZeneca vaccine. 

GBS is a rare immune disorder that causes nerve inflammation and can result in pain, numbness, muscle weakness and difficulty walking. In many cases it resolves within months but can sometimes take up to two years. 

A causal link between GBS and the AstraZeneca vaccine has not been confirmed in Australia or overseas. However, the TGA is currently doing a detailed investigation of GBS reports along with other serious adverse event reports that relate to the nervous system. This involves looking more closely at whether these suspected cases meet the clinical criteria for GBS, and comparing the number of observed cases to those that would be expected generally in unvaccinated people. We are also collaborating with our international regulatory counterparts and awaiting the results of an assessment of this issue by the European Medicines Agency. 

Up-to-date information about the expected side effects of the AstraZeneca COVID-19 vaccine can be found in the Consumer Medicine Information (for consumers) and Product Information (for health professionals).

Comirnaty (Pfizer) vaccine

Side effects to the Comirnaty vaccine continue to be reported to the TGA and are consistent with what has been observed in the clinical trials and by other medicine regulators overseas. So far, approximately 3.2 million doses of the Comirnaty vaccine have been administered.

Myocarditis and pericarditis

The TGA continues to monitor reports of myocarditis (inflammation of the heart) and pericarditis (inflammation of the membrane around the heart) following a safety concern in the US and Israel.

To 4 July 2021, the TGA has received 38 cases of suspected myocarditis or pericarditis – 13 reports were in men and 25 were in women. Of the men, five were aged 17–23 years, while the others were aged 41–72 years. The women were aged 22–65 years old with the most aged in their 20s and 30s. At the time of reporting, the majority of individuals had recovered or were recovering.

Overseas cases of myocarditis and pericarditis have mostly been in young men after the second Comirnaty dose. As we have limited experience of Comirnaty both in this age group and after the second dose, the TGA is considering international evidence in its ongoing investigation of this issue. 

On 23 June 2021, a review by the US CDC’s Advisory Committee on Immunization Practices advised that myocarditis and pericarditis following the Comirnaty vaccine are extremely rare side effects which are usually mild. The US Food and Drug Administration (FDA) has since added a warning to the product information.

The TGA is currently working with Pfizer to add a warning statement to the Product Information and include myocarditis and pericarditis as an adverse event identified through post-marketing experience.

We know that myocarditis and pericarditis are much more common with COVID-19 infection and the risks to the heart can be more severe in this context. The benefits of protection against COVID-19 far outweigh these rare and generally mild side effects.

We encourage people to seek medical attention if they experience symptoms that could suggest myocarditis or pericarditis such as of chest pain, shortness of breath and palpitations. Typically these have occurred within seven days of vaccination, and more commonly after the second dose of Comirnaty.

Up-to-date information about Pfizer Comirnaty can be found in the Consumer Medicine Information (for consumers) and Product Information (for health professionals).