COVID-19 vaccine weekly safety report - 23-12-2021

Reported side effects for COVID-19 vaccines

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 19 December 2021, we have received about 2,900 reports after vaccination with Comirnaty (Pfizer) and Spikevax (Moderna). The most commonly reported reactions in this age group are:

• chest pain
• headache
• dizziness
• nausea
• fever.

Booster doses

The TGA is monitoring the safety of booster vaccine doses. It is not expected that the type of side effects will be different to first and second vaccine doses based on the results of clinical trials, and observations from regulators overseas where more booster doses have been given.

The Comirnaty (Pfizer) and Spikevax (Moderna) vaccines are approved for use as booster doses. As the Omicron and Delta variants continue to cause disease in Australia, the Australian Technical Advisory Group on Immunisation (ATAGI) recommends booster vaccination for adults. For people who are immunocompromised, a third dose is given as part of their primary vaccine course. This is not considered to be a ‘booster’. Click here for the latest vaccination recommendations from ATAGI.

To 19 December 2021, we have received approximately 400 reports of suspected adverse events identified as a third or booster dose. One of these reports was a myocarditis report following a third dose of Comirnaty (Pfizer).

The most common adverse event reported to the TGA following a booster dose is swollen lymph nodes (also called lymphadenopathy). This is a normal and known side effect of vaccines and occurs when the immune system is stimulated. Swollen lymph nodes were observed in the clinical trials. For Comirnaty (Pfizer), swollen lymph nodes occurred more frequently in clinical trials after a third or booster dose (5% of people) than after the first or second doses (less than 1% of people). For Spikevax (Moderna), this occurred in up to 10% of people.

Information about swollen lymph nodes is already included in the Product Information documents. Swelling may be noticed near the injection site, for example in an armpit, within a few days of vaccination. This normally resolves without treatment after a week or so. People should seek medical attention if swelling persists for more than a few weeks to rule out other causes.

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. As the number of people being vaccinated has increased, so has reporting of fatal events with a temporal association with vaccination. Review of these individual reports and patterns of reporting does not suggest that the vaccines played a role in the vast majority of these deaths.

The TGA closely reviews all adverse events after COVID-19 vaccination where a fatal outcome is reported. Read more about this process in a previous report. Since the beginning of the vaccine rollout to 19 December 2021, about 41.3 million doses of COVID-19 vaccines have been given. The TGA has identified 11 reports of death that were linked to vaccination from 719 reports received and reviewed. The deaths linked to vaccination occurred after the first dose of Vaxzevria (AstraZeneca) – 8 were thrombosis with thrombocytopenia syndrome (TTS) cases, 2 were linked to Guillain-Barre Syndrome (GBS) and one was a case of immune thrombocytopenia (ITP).

AusVaxSafety – a national survey on COVID-19 vaccine safety

This ongoing survey actively collects responses from Australians about adverse events after they have received a COVID-19 vaccine. The survey tells us what proportion of people experience an adverse event and what the most common reactions are. It also measures the percent of people who went to the doctor or missed work or study because of an adverse event. Reassuringly, survey results largely reflect what was seen in the clinical trials, with injection-site reactions, fatigue, headache, and muscle and joint pain being the most common reactions.

Results are given for everyone who took the survey, which is about 5 million Australians so far. Data is presented for each vaccine and for the first, second and third or booster doses. Vaccine safety data is also given for subgroups of the population including:

• Aboriginal and Torres Strait Islander people
• adolescents
• people affected by cancer or who have received a transplant
• pregnant women

For more details and results of the survey, go to the AusVaxSafety website.

Comirnaty (Pfizer) mRNA vaccine

To 19 December 2021, about 26.2 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 19 December 2021, about 1.5 million doses of Spikevax (Moderna) have been administered in Australia. The TGA provisionally approved the use of Spikevax (Moderna) as a booster dose on 8 December 2021.

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 other potential side effects, can be found in the Consumer Medicine Information (for consumers) and Product Information (for health professionals).

Vaxzevria (AstraZeneca) vaccine

To 19 December 2021, about 13.6 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).

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

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.

ATAGI advises that people who develop myocarditis attributed to their first vaccine dose 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.

What are myocarditis and pericarditis?

Myocarditis is inflammation of the heart, and pericarditis is inflammation of the membrane around the heart. They can occur as rare adverse events after vaccination with the mRNA vaccines Comirnaty (Pfizer) and Spikevax (Moderna).

When do myocarditis and pericarditis occur?

Cases typically occur within 10 days, with symptom onset often within 5 days of vaccination. Our analysis indicates that most of the patients with likely myocarditis experienced symptoms within 3 days of vaccination.

How common are myocarditis and pericarditis?

In some countries, higher rates of myocarditis and pericarditis have been reported with Spikevax (Moderna) than with Comirnaty (Pfizer). In Australia, we are also seeing slightly higher overall estimated rates of myocarditis for Spikevax – 2.5 cases per 100,000 Spikevax doses versus 1.6 cases per 100,000 Comirnaty doses. However, statistical analysis shows that there is more uncertainty around the reporting rate for Spikevax (likely to be between 1.9 and 3.3 cases per 100,000 doses) than for Comirnaty (likely to be between 1.5 and 1.7 cases per 100,000 doses).

Who is at risk of these heart problems?

Myocarditis is more commonly reported in young men and teenage boys after the second dose (6–12 cases in 100,000 people after vaccination with Comirnaty and 8–16 cases per 100,000 after vaccination with Spikevax doses). However, even in this population it remains rare.

A European review of myocarditis and pericarditis data in teenage boys and young men (12-29 years old) found for Comirnaty, there were 2–6 extra cases of myocarditis per 100,000 vaccinated individuals compared to unvaccinated individuals. For Spikevax, there were 13–19 extra cases of myocarditis per 100,000 vaccinated individuals compared to unvaccinated individuals.*

*Correction: in the last 2 TGA vaccine safety reports, we incorrectly quoted the number of extra cases of myocarditis per 100,000 vaccinated individuals as ‘less than 1 extra case’ for Comirnaty and ‘1–2 extra cases’ for Spikevax. This has now been corrected (see above). We apologise for this error.

How serious is myocarditis?

Myocarditis is often mild, and cases usually resolve after a few days with treatment and rest. Some cases are more serious and need to be treated in hospital. Our analysis has found about 60% of the patients with likely myocarditis were admitted to hospital. Four people were treated in intensive care, representing about 1% of all cases classified as likely myocarditis. This number has decreased since last week because one case was reassessed as unlikely to be myocarditis after further expert review. Most patients admitted to hospital were discharged within 4 days.

What symptoms should I look out for?

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.

What does the TGA know about Australian myocarditis and pericarditis cases?

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.

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.

*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. For all cases of suspected myocarditis, where possible, other known causes of the patient’s symptoms or test results are ruled out before cases are classified.

†The youngest case classified as ‘likely myocarditis’ to date was 12 years old.

£ Classification of likely pericarditis is based on the patient’s symptoms and test results and the absence of other known causes of pericarditis.

Rates of myocarditis by age and dose are given for Comirnaty (Pfizer) and Spikevax (Moderna) in Table 2. The estimated reporting rates in Australia appear similar to overseas rates. The rates for Spikevax (Moderna) are less certain due to low numbers of cases overall.

*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 pericarditis 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

What is TTS?

Thrombosis with thrombocytopenia syndrome (TTS) is a rare but serious adverse event linked to the Vaxzevria (AstraZeneca) vaccine. People with TTS have blood clots and low blood platelets.

When does TTS occur?

TTS symptoms usually start between 4–30 days after vaccination. In Australia, cases most often occurred about 2 weeks after vaccination.

How common is TTS?

TTS is a rare adverse event. 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.

Who is at risk of TTS?

Younger women seem to be slightly more likely to have serious outcomes from TTS as they more often experience clots in unusual locations, such as the brain or abdomen. These cases are classified as ‘Tier 1’. People under 60 years are more likely to be classified as Tier 1 and/or require treatment in intensive care.

How serious is TTS?

TTS can be a serious illness and most people require treatment in hospital. Occasionally, TTS is fatal. In Australia, the risk of dying from TTS after vaccination is about one in a million (people receiving a first dose). Of the 170 people who developed TTS, 8 of them died – 6 of these were women.

What TTS symptoms should I look out for?

It is important for people with symptoms of TTS to get medical attention early as this may help to prevent more serious complications. 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.

While TTS is very rare, some people may have concerns that they wish to 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.

Where can I find more information about TTS?

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.

What does the TGA know about Australian TTS cases?

From about 13.6 million vaccine doses, there have been 170 cases of TTS. Of these, 147 (83 confirmed, 64 probable) related to a first dose of Vaxzevria (AstraZeneca) and 23 to a second dose (5 confirmed, 18 probable). No new cases were reported this week (see Table 3).

‡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). 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.

‡ Rates of TTS are calculated as of 9 December 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).

*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

What is GBS?

GBS is a rare but sometimes serious immune disorder affecting the nerves and can result in pain, numbness, muscle weakness and difficulty walking.

When does GBS occur?

GBS can occur when the immune system is activated and has been associated with infections, including COVID-19, and vaccines. GBS usually occurs days or weeks after an infection or vaccination. However, sometimes a trigger for GBS cannot be identified. The expected time period for onset of GBS symptoms is 2–42 days after vaccination.

How common is GBS?

GBS following vaccination is rare. In Australia, it has been reported in about one in every 100,000 people following the Vaxzevria (AstraZeneca) vaccine.

To 19 December 2021, the TGA has received 168 reports of suspected GBS occurring after vaccination with Vaxzevria (AstraZeneca). It is expected that some of these cases may not be related to vaccination, as GBS can occur after common viral infections and some types of gastroenteritis. In addition, numbers may fluctuate as duplicate cases are identified and processed.

Who is at risk from GBS?

Emerging evidence suggests that GBS may be a rare adverse event associated with Vaxzevria (AstraZeneca). There are currently no identified risk factors for GBS. However, in the general population it is more common in people aged over 60 years.

How serious is GBS?

GBS is a serious condition that can occasionally lead to death. While many cases of GBS resolve within months, recovery in some people can take years. There have been two fatal cases of GBS linked to the Vaxzevria (AstraZeneca) vaccine in Australia. However, there was some uncertainty around this link as GBS occurs in people who have not received a vaccine and sometimes there is no obvious trigger identified.

What GBS symptoms should I look out for?

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, pain 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.

What is the TGA doing about GBS cases?

The benefits of Vaxzevria (AstraZeneca) continue to outweigh the risks. Health professionals should be aware of the possible signs and symptoms of GBS in people who have been vaccinated to ensure correct diagnosis and so that treatment can be started early.

There is growing evidence of a possible link between GBS and Vaxzevria (AstraZeneca) following rigorous investigations of safety data by the TGA and other international regulators. Further updates to the Vaxzevria (AstraZeneca) Product Information are expected to reflect this.

Immune thrombocytopenia (ITP)

What is ITP?

ITP is a rare immune reaction that occurs when platelets, which help blood to clot, are mistakenly destroyed.

When does ITP occur?

ITP can occur after a viral infection or a vaccine. Information from other vaccines suggest it most commonly develops within 6 weeks of vaccination.

How common is ITP?

It is very rare after COVID-19 vaccination. In Australia, ITP has been reported in less than one in every 100,000 people following the Vaxzevria (AstraZeneca) vaccine.

To 19 December 2021, the TGA has received 84 reports of suspected ITP following vaccination with Vaxzevria (AstraZeneca). This number has decreased since last week following a review which identified some duplicate reports and reassessed some cases with new information. 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.

Who is at risk of ITP?

There are currently no identified risk factors for ITP following vaccination with a COVID-19 vaccine.  

How serious is ITP?

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. In a very small number of people it can be fatal. 

In Australia, there has been one report of a fatal case of ITP linked to vaccination with Vaxzevria (AstraZeneca). Following an investigation by the TGA, the Product Information has been updated to include a warning about ITP. Other suspected cases of ITP have not been definitively linked to vaccination.

What ITP symptoms should I look out for?

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.

Useful links

Watch this video to find out how the TGA monitors and reports the safety of COVID-19 vaccines – 26 November 2021

ATAGI statement on the Omicron variant and timing of COVID-19 booster vaccination – 18 December 2021

Top 3 COVID-19 vaccine questions – children and vaccine, 11 year olds and vaccine, and boosters for ages 12-17 – 21 December 2021

Top 3 COVID-19 vaccine questions – Mental health support, anxiety with travel, and recharging after a huge year – 16 December 2021

Top 3 COVID-19 vaccine questions – Boosters, assessing Omicron severity, and anxiety around holiday period – 14 December 2021

Myocarditis and pericarditis following COVID-19 mRNA vaccines – Melbourne Vaccine Education Centre – 11 November 2021

COVID-19 vaccines: Frequently asked questions – 20 December 2021

COVID vaccines – is it true? – 17 December 2021

Vaccination among COVID-19 cases in the NSW Delta outbreak – 8 November 2021

RMIT ABC Fact Check

Latest advice on COVID-19 vaccination for pregnant and breastfeeding women – 18 August 2021

Coronavirus (COVID-19) case numbers and statistics

Australia’s COVID-19 vaccine rollout

TGA COVID-19 vaccines hub

Australian Government Department of Health COVID-19 vaccines hub

COVID vaccine information in your language

AusVaxSafety (active surveillance activities and information)

COVID-19 vaccine symptom checker

Database of Adverse Event Notifications (DAEN)

Comirnaty (Pfizer) vaccine – phase III clinical trial

Vaxzevria (AstraZeneca) vaccine – phase III clinical trial

Spikevax (Moderna) vaccine – phase III clinical trial