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COVID-19 vaccine weekly safety report - 25-11-2021

Three COVID-19 vaccines are currently in use in Australia – Comirnaty (Pfizer), Spikevax (Moderna) and Vaxzevria (AstraZeneca). These vaccines meet the TGA’s high standards for quality, safety and effectiveness.

The TGA closely monitors reports of suspected side effects (also known as adverse events) to the COVID-19 vaccines. This is the most intense safety monitoring ever conducted in Australia.

We encourage people to report suspected side effects, even if there’s only a very small chance a vaccine was the cause. This provides valuable data that helps us identify trends or spikes that might reveal potential safety issues. Often, however, these events are not caused by the vaccines. Learn more about causality and our COVID-19 vaccine safety monitoring and reporting activities.

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Summary

  • Vaccination against COVID-19 is the most effective way to reduce deaths and severe illness from infection. The protective benefits of vaccination continue to far outweigh the potential risks. 

  • Like all medicines, COVID-19 vaccines may cause some side effects. The most frequently reported include injection-site reactions (such as a sore arm) and more general symptoms, like headache, muscle pain, fever and chills. This reflects what was seen in the clinical trials. 

  • We are carefully monitoring and reviewing reports of: 

  • Myocarditis is a known but very rare side effect of Comirnaty (Pfizer) and Spikevax (Moderna). It is usually temporary, with most people getting better within a few days. Myocarditis is reported in 1–2 in every 100,000 people who receive Comirnaty (Pfizer), although it is more common in young men and teenage boys after the second dose (5–11 cases per 100,000 doses). 

    • To 21 November 2021, the TGA has received 341 reports which have been assessed as likely to be myocarditis from about 23.9 million doses of Comirnaty (Pfizer).

  • Thrombosis with thrombocytopenia syndrome (or TTS) is a very rare but serious side effect of Vaxzevria (AstraZeneca). Our analysis shows it is reported in about 2 in every 100,000 vaccinated people following the first dose. The risk of TTS is much lower after the second dose (0.3 in every 100,000 vaccinated people).

    • One new case of TTS was reported this week, taking the total to 164 cases from about 13.4 million doses of Vaxzevria (AstraZeneca).

Total adverse event reports to 21 November 2021

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2.2
Reporting rate per 1000 doses
83,301
Total AEFI reports received
38,454,860
Total doses administered
41,163
Total reports for Vaxzevria
40,086
Total reports for Comirnaty
1,711
Total reports for Spikevax
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To 21 November 2021, the total number of adverse event reports received where the brand of the COVID-19 vaccine was not specified was 425.

Reported side effects for COVID-19 vaccines

Learn more about how the TGA identifies and responds to safety issues

The most frequently reported side effects suspected to be associated with the vaccines include injection-site reactions, such as a sore arm, headache, muscle and joint pain, fever and chills.

The TGA is closely monitoring reports in people aged under 18 years. To 21 November 2021, we have received about 2200 reports after vaccination with Comirnaty (Pfizer) and Spikevax (Moderna). The most commonly reported reactions are:

  • chest pain

  • dizziness

  • headache

  • nausea

  • fever.

For more information on side effects reported in adolescents, check out the AusVaxSafety survey results for those aged under 20 years old.

The TGA is also monitoring the safety of booster vaccine doses. It is not expected that the safety profile will be different to first and second vaccine doses based on early observations overseas. However, we will report any emerging safety concerns if they arise.

Anyone can report a suspected side effect, either:

  • directly to the TGA

  • through a health professional

  • by calling the NPS MedicineWise Adverse Medicine Events phone line for consumers.

You can report anonymously. 

Learn more about how to report a suspected side effect to a COVID-19 vaccine.

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Reports of death in people who have been vaccinated

Large scale vaccination means that some people will experience a new illness or die within a few days or weeks of vaccination. These events are often coincidental, rather than being caused by the vaccine.

The TGA reviews all deaths reported in people who have been recently vaccinated. As the number of people being vaccinated has increased, so has reporting of fatal events with a coincidental association with vaccination. Our review of individual reports and patterns of reporting does not suggest that the vaccines played a role in the vast majority of these deaths.

Since the beginning of the vaccine rollout to 21 November 2021, about 38.5 million doses of COVID-19 vaccines have been administered. The TGA has found 9 reports of death that were linked to immunisation from 682 reports received and reviewed. The overwhelming majority of deaths reported occurred in people aged 65 years and older. The deaths linked to immunisation occurred after the first dose of Vaxzevria (AstraZeneca) – 8 were TTS cases and one was a case of immune thrombocytopenia (ITP).

Comirnaty (Pfizer) mRNA vaccine

To 21 November 2021, about 23.9 million doses of Comirnaty (Pfizer) have been administered in Australia.

The TGA is actively investigating reports of myocarditis (inflammation of the heart) and/or pericarditis (inflammation of the membrane around the heart) associated with mRNA vaccines. We continue to work with international regulators on this safety signal (see below). 

Up-to-date information for Comirnaty (Pfizer), including details of potential side effects , can be found in the Consumer Medicine Information (for consumers) and Product Information (for health professionals).

Spikevax (Moderna) mRNA vaccine

To 21 November 2021, about 1.1 million doses of Spikevax (Moderna) have been administered in Australia.

The TGA is actively investigating reports of myocarditis (inflammation of the heart) and/or pericarditis (inflammation of the membrane around the heart) associated with mRNA vaccines. We continue to work with international regulators on this safety signal (see below). 

Up-to-date information for Spikevax (Moderna), including details of potential side effects, can be found in the Consumer Medicine Information (for consumers) and Product Information (for health professionals).

Vaxzevria (AstraZeneca) vaccine

To 21 November 2021, about 13.4 million doses of Vaxzevria (AstraZeneca) have been administered in Australia. 

The TGA is closely monitoring rare reports of blood clots with low blood platelets (also called thrombosis with thrombocytopenia syndrome or TTS) linked to this vaccine. We are also monitoring reports of immune thrombocytopenia (ITP) and Guillain-Barre Syndrome (GBS). See below for more details.

Up-to-date information, including details of these and other potential side effects can be found in the Consumer Medicine Information (for consumers) and Product Information (for health professionals).

Myocarditis and pericarditis with mRNA vaccines

Myocarditis (inflammation of the heart) and pericarditis (inflammation of the membrane around the heart) are rare effects on the heart that may occur after vaccination with the mRNA vaccines Comirnaty (Pfizer) and Spikevax (Moderna). Cases typically occur within 10 days, and usually resolve after a few days following treatment and rest. In Australia, myocarditis is reported in 1–2 out of every 100,000 people after receiving the Comirnaty (Pfizer) vaccine. While it is more commonly reported in young men and teenage boys after the second dose (5–11 cases in 100,000 people), it remains rare. 

The number of reports of myocarditis is increasing each week, which is expected as the number of vaccine doses given also increases each week. We are closely monitoring the rates of myocarditis for all age groups and sex. While there are some fluctuations from week to week, especially in subgroups with small numbers of reports, rates of reporting of myocarditis in Australia are consistent with rates reported internationally.

Myocarditis is seen much more commonly in people who become infected with COVID-19 than in people who are vaccinated. A preliminary study from the United States found the rate of myocarditis in young men after COVID-19 is approximately 45 cases per 100,000 infections. It is important to note that this study has not yet been peer-reviewed. These findings are consistent with other information published by the Centers for Disease Control and Prevention in the US on myocarditis as a complication of COVID-19 infection. The Australian Technical Advisory Group on Immunisation (ATAGI) continues to emphasise that the protective benefits of the mRNA vaccines far outweigh the rare risk of these side effects in all eligible age groups

We encourage people to seek medical attention if they experience symptoms that could suggest myocarditis or pericarditis. This includes chest pain, palpitations (irregular heartbeat), fainting or shortness of breath, particularly if they occur within 1–5 days of vaccination. 

Initial tests for those presenting with symptoms include ECG, troponin levels and chest X-ray. Brief guidance on the initial assessment of children and adolescents with symptoms has been published by the Paediatric Research in Emergency Departments International Collaborative (PREDICT) network

ATAGI advises that people who develop myocarditis attributed to their first dose of Comirnaty (Pfizer) should defer further doses of an mRNA COVID-19 vaccine and discuss this with their treating doctor. 

For those with suspected pericarditis after a first dose, future dose recommendations depend on test results and the person’s age and sex. Refer to expert Guidance on myocarditis and pericarditis after mRNA COVID-19 vaccines for more information.

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Details of Australian cases to 21 November 2021

Like other countries, we have observed a higher-than-expected number of cases of myocarditis in vaccinated compared to unvaccinated individuals for Comirnaty (Pfizer). The Global Advisory Committee on Vaccine Safety at the World Health Organization has recently stated that current evidence suggests a likely causal association between myocarditis and the mRNA vaccines. 

In some countries, higher rates of myocarditis and pericarditis have been reported with Spikevax (Moderna) than with Comirnaty (Pfizer). Because the number of cases of myocarditis reported after Spikevax (Moderna) in Australia is small, we are not yet able to calculate reliable reporting rates for it or to see any difference in risk between the 2 vaccines. The current overall estimated rates (for the entire population) of myocarditis for Comirnaty and Spikevax are similar (1.4 cases per 100,000 Comirnaty doses versus 1.6 cases per 100,000 Spikevax doses). However, statistical analysis shows that there is more uncertainty around the reporting rate for Spikevax (likely to be between 1.1 and 2.4 cases per 100,000 doses) than for Comirnaty (likely to be between 1.3 and 1.6 cases per 100,000 doses). 

Reports received by the TGA of suspected myocarditis and pericarditis for the mRNA vaccines are provided in Table 1. We have reviewed these reports against an internationally accepted criteria to classify the likelihood of myocarditis. This assessment does not determine whether cases have been caused by vaccination. 

Table 1. Reports of suspected myocarditis and pericarditis received by the TGA

Comirnaty (Pfizer)

(23.9 million doses given)

Spikevax (Moderna)

(1.1 million doses given)

All cases

Cases in adolescents (12–17 years)

All cases

Cases in adolescents (12–17 years)

Suspected myocarditis cases*

650

129

30

11

Likely myocarditis†‡

Level 1

35

6

0

0

Level 2

261

83

13

8

Level 3

45¥

5

1

Unlikely myocarditis

121

8

3

1

Insufficient information 

188

24

9

1

Suspected pericarditis cases

1546

125

70

5

*Cases reporting both myocarditis and pericarditis are included in suspected myocarditis cases

‡ Cases classified as level 1 are confirmed to be myocarditis based on strong clinical evidence including the patient’s symptoms, and results of tests and imaging indicating a diagnosis of myocarditis. Level 2 cases are probably myocarditis based on a combination of symptoms and routine tests for heart conditions. Level 3 cases are possibly myocarditis based on symptoms and a doctor’s report that myocarditis is the most likely diagnosis in the absence of medical tests and investigations. Other known causes of the patient’s symptoms or test results are ruled out before all cases are classified.

†The youngest case classified as ‘likely myocarditis’ to date was 12 years old.
¥The number of level 3 cases has decreased since last week following reclassification of some cases as level 2 after receiving additional clinical information. Also, some cases were identified as duplicates and removed.

Of the cases classified as likely to be myocarditis, most of the patients experienced symptoms within 3 days of vaccination. Around half of the patients were admitted to hospital with 9 being treated in intensive care. We previously reported 11 patients had been treated in ICU but following further review this has been corrected to 9. Most patients treated in hospital were discharged within 4 days.

As we have received limited adverse event reports for Spikevax (Moderna), our analysis of likely myocarditis cases by age and dose focuses on data for the Comirnaty (Pfizer) vaccine (see Table 2). The estimated reporting rates in Australia appear similar to overseas rates. 

Table 2. Rates of myocarditis cases (levels 1-3) following Comirnaty (Pfizer)

Age (years)

All doses

Second doses

Rate* per 100,000 doses

Rate* per 100,000 doses

Male

Female

Male

Female

12-17

6.7

1.4

10.8

2.6

18-29

3.5

1.2

5.3

1.6

30-39

1.5

0.6

1.6

0.5

40-49

0.7

0.7

0.9

0.9

50-59

0.5

0.2

0.2

0.3

60-69

0.0

0.4

0.0

0.0

70+

0

0.2

0

0

All ages*

2.1

0.8

3.0

1.0

*The rate includes cases of myocarditis that occurred after vaccination but may not be vaccine related. The number of younger people vaccinated is still relatively low in Australia, so estimated reporting rates are based on limited data.

We continue to monitor and review Australian data on myocarditis and will provide regular updates in this report as more information becomes available. We are also working closely with international medicines regulators to share emerging safety information.

For more information, see guidance on myocarditis and pericarditis developed by ATAGI and the Cardiac Society of Australia and New Zealand (CSANZ).

Thrombosis with thrombocytopenia syndrome

Thrombosis with thrombocytopenia syndrome (TTS) is a rare but serious adverse event linked to the Vaxzevria (AstraZeneca) vaccine. It is characterised by blood clots and low blood platelets which develop within a few days or weeks after vaccination. In Australia, it occurs in about 2 out of every 100,000 people after a first dose. The risk of TTS after a second vaccine dose appears to be much lower and is estimated to be 0.3 out of every 100,000 people after a second dose. 

Early detection of TTS may help to prevent more serious complications developing. Guidance for health professionals is now available which outlines when to suspect TTS, initial tests that can be performed in primary care and when to refer people for emergency care. Patients presenting with low platelets and a headache should be thoroughly investigated for blood clots in the brain, including careful review of imaging results to identify early, small clots. The Royal Australian and New Zealand College of Radiologists have published imaging recommendations for patients with suspected TTS.

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

  • severe or persistent headache, blurred vision, confusion or seizures

  • 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.

While TTS is very rare, some people may have concerns that they can discuss with their doctor. ‘Weighing up the potential benefits against risk of harm from COVID-19 Vaccine AstraZeneca’ includes information to help people make informed decisions about vaccination.

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Details of TTS cases

From about 13.4 million vaccine doses, there have been 164 cases of TTS. Of these, 143 (81 confirmed, 62 probable) related to a first dose of Vaxzevria (AstraZeneca) and 21 to a second dose (6 confirmed, 15 probable). This includes one new case of probable TTS reported this week (see Table 3).

Table 3: Newly confirmed and probable TTS cases for the week of 19-25 November 2021‡ 

New confirmed TTS

New probable TTS

No cases

One case (following a first dose):

  • 67-year-old woman from Victoria

As previously reported, the TGA determines whether a report is likely to represent TTS by assessing cases against accepted criteria established by the UK’s Medicines and Healthcare products Regulatory Agency. Cases may be reclassified as further information becomes available.

When assessed against the criteria used by the US Centers for Disease Control and Prevention (CDC), approximately one-third of the cases reported to the TGA after a first dose are classified as Tier 1 (Table 4). These cases tend to have more serious outcomes involving clots in unusual locations, such as the brain or abdomen. Women in younger age groups seem to be slightly more likely to develop these kinds of clots. Australian data indicates that patients aged under 50 years are more likely to be classified as Tier 1 and/or require treatment in intensive care. 

Cases reported after a second vaccine dose are much less likely to be classified as Tier 1 with most people having clots in common locations, such as the lungs or legs. The majority of these cases occurred in people over the age of 60 years old. 

Table 4: Australian TTS cases to date by age and CDC classification. A. First dose cases

Age

Reported cases

(6.9 million doses given)

Tier 1 CDC classification†

Reports per 

100,000 doses‡

<30 years

8

2

2.0

(<50 years)

30-39

5

4

40-49

11

6

50-59

33

18

3.0

60-69

34

10

1.7

70-79

37

10

2.2

80+

15

1.8

All ages

143

(71 men, 72 women)

54

(18 men, 36 women)

2.1

 
B. Second doses cases

Age

Reported cases

(6.6 million doses given)

Tier 1 CDC classification†

Reports per 

100,000 doses‡

<30 years

0

0

0

(<50 years)

30-39

0

0

40-49

0

0

50-59

3

1

0.4

(≥50 years)

60-69

5

1

70-79

9

1

80+

4

0

All ages

21

(14 men, 7 women)

3

(2 men, 1 woman)

0.3

‡ Rates of TTS are calculated as of 4 November 2021 to account for the time to onset of TTS. 

These rates are estimates of risk based on small numbers of cases so far. Aggregated rates are given for some age ranges where the number of cases for a 10-year age bracket is too low to calculate reliable estimates.

† The US CDC classification of Tier 1 is defined as 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).  

Cases of TTS have most often occurred about 2 weeks after vaccination, although the time to onset or diagnosis varies (Table 5). Eight people have died as a result of TTS – 6 of these were women. In Australia, the risk of dying from TTS after vaccination is about one in a million (people receiving a first dose), and somewhat less than this when both doses are taken into consideration. 

Table 5: Time to onset, treatment and outcomes for TTS cases*

First dose

Second dose

Median time to onset/ diagnosis 

Median (range)

13 days (1-94)

10 days (2-34)

Treated in ICU

At any point

46

1

Currently

0

0

Outcome†

Discharged

131

21

In hospital

3

0

Fatal

8

0

*Data is based on the most recent medical information available to the TGA for first and second dose TTS cases
†As previously reported, one patient died from unrelated medical conditions while being treated for TTS. The outcome for this patient is not included in this table.

Guillain-Barre Syndrome

In Australia, Guillain-Barre Syndrome (GBS) has been reported in about one in every 100,000 people following the Vaxzevria (AstraZeneca) vaccine. It is a rare but sometimes serious immune disorder affecting the nerves and can result in pain, numbness, muscle weakness and difficulty walking. GBS can occur when the immune system is activated. It has been associated with COVID-19 and other infections. 

Following rigorous investigations by the TGA and other international regulators, a clear link between GBS and Vaxzevria (AstraZeneca) has not been established. However as a precautionary measure in response to rare cases following vaccination, warning statements about GBS have been added to the Vaxzevria (AstraZeneca) Product Information.

We encourage people to seek medical attention if they experience symptoms that could suggest GBS as early medical care can reduce severity and improve outcomes. Symptoms to look out for include weakness and paralysis in the hands or feet that can progress to the chest and face over a few days or weeks. Symptoms tend to affect both sides of the body.

To 21 November 2021, the TGA has received 150 reports of suspected GBS occurring after vaccination with Vaxzevria (AstraZeneca). It is expected that some suspected cases may not be related to vaccination, as GBS can occur after common viral infections and some types of gastroenteritis.

Immune thrombocytopenia

In Australia, immune thrombocytopenia (ITP) has been reported in less than one in every 100,000 people following the Vaxzevria (AstraZeneca) vaccine. It is a rare immune reaction that can occur after a viral infection or vaccination when platelets, which help blood to clot, are mistakenly destroyed. 

Following an investigation by the TGA, the Vaxzevria Product Information has been updated to include a warning about ITP. Apart from one previously reported fatal case that was assessed by an expert Vaccine Safety Investigation Group as being likely to be vaccine related, other suspected cases of ITP have not been definitively linked to vaccination.

In many cases ITP is mild with up to a third of people having no symptoms at all, or only minor bruising. However, about 5% develop severe bleeding. 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.

To 21 November 2021, the TGA has received 90 reports of suspected ITP following vaccination with Vaxzevria (AstraZeneca). These patients had an extremely low platelet count, and signs of thrombocytopenia which may include unusual bruising, a nosebleed and/or blood blisters in the mouth. Their symptoms occurred in a timeframe that suggested they could be linked to vaccination and no other obvious cause was identified based on the information provided to the TGA.