COVID-19 vaccine weekly safety report - 07-04-2021

A number of factors influence reporting behaviour and reporting rates. Differences in reporting rates do not indicate any safety concerns specific to particular jurisdictions.

AEFI reports received in the week 29 March - 4 April 2021

Last week, the TGA received a total of 1218 AEFI reports for COVID-19 vaccines, including 347 for the Comirnaty vaccine, 845 for the AstraZeneca COVID-19 vaccine, and 26 reports where the vaccine tradename was not reported. The most common adverse events reported for COVID-19 vaccines during this period were:

• Headache
• Fever
• Muscle pain
• Chills
• Nausea

Adverse events reported to the TGA may not be caused by the vaccine. Learn more about causality.

Not all adverse events are reported, especially for minor and well-known side effects. Learn more about reporting levels.

The information the TGA receives in reports reflects the view of the reporter. As the data entry and analysis of incoming reports is ongoing, the information may change as additional reports are completed, data quality is reviewed or further information is provided. Total numbers may also change as duplicate reports are identified.

Analysis of adverse event reports by product received up to and including 28 March 2021

Comirnaty BNT162b2 (mRNA) – Pfizer Australia Pty Ltd

Frequently reported adverse events

The most frequently reported adverse events for the Comirnaty vaccine, from most to least common, were:

• Headache
• Nausea
• Dizziness
• Fatigue
• Muscle pain

The occurrence of these adverse events is consistent with what is already known about the Comirnaty vaccine. Headache, injection site reaction, nausea, fatigue and muscle pain were commonly reported adverse events in clinical trials. Dizziness is a common reaction to vaccination that can be caused by the body’s reaction to pain or feeling anxious about an injection.

Adverse events of special interest

The TGA, like other vaccine safety monitoring programs around the world, closely monitors for specific adverse events known as ‘adverse events of special interest’. This close monitoring helps us to confirm the safety profile of COVID-19 vaccines, particularly with respect to possible side effects that may occur rarely. We conduct analyses to compare the number of reports of these events against the expected rate of events.

Adverse events of special interest reported for the Comirnaty vaccine were:

• Anaphylaxis (33 reports)
• Bleeding disorder (7 reports)
• Facial weakness (6 reports)
• Seizure (6 reports)
• Cardiac event (2 reports)
• Loss of sense of taste or smell (2 reports)

We are continuing to carefully review the reports of possible anaphylaxis following Comirnaty to determine whether they are consistent with true anaphylaxis and whether they may have been caused by the vaccine. Review of these cases indicates that only 11 meet the case definition criteria for anaphylaxis. Further detailed analysis of the observed rate of anaphylaxis in Australia is ongoing. Anaphylaxis remains a very rare side effect of the Comirnaty vaccine.   

Guidance on the management of possible anaphylaxis remains as per the Product Information. Routine vaccination procedures include keeping people under observation for 15 minutes after vaccination and having appropriate medical treatment on hand so that anaphylaxis can be rapidly managed, if it occurs. A second dose of Comirnaty should not be given to those who have experienced anaphylaxis to the first dose.

Bleeding and blood clot disorders, such as stroke, pulmonary embolism and deep vein thrombosis, are being monitored because of a theoretical link with COVID-19 disease. These are common conditions rather than the unusual clotting disorder associated with very low platelets (thrombocytopenia) being investigated in relation to the AstraZeneca COVID-19 vaccine.

Facial weakness has been reported rarely in clinical trials for Comirnaty.

Seizures and cardiac events are being monitored because of a theoretical link with vaccines. They can also occur around the time of immunisation for reasons not related to the vaccine.

The loss of sense of taste or smell is being monitored because of a theoretical link with COVID-19 disease. It may also be a non-specific symptom associated with feeling unwell.

Our review does not suggest an increased risk of any of the above adverse events of special interest with the Comirnaty vaccine.

Further information about Comirnaty can be found in the Consumer Medicine Information.

COVID-19 Vaccine AstraZeneca (ChAdOx1-S) – AstraZeneca Pty Ltd

Frequently reported adverse events

The most frequently reported adverse events for the AstraZeneca COVID-19 vaccine, from most to least common, were:

• Headache
• Fever
• Muscle pain
• Chills
• Fatigue

The occurrence of these adverse events is consistent with what is already known about the vaccine. They were commonly reported in clinical trials.

Adverse events of special interest

The TGA, like other vaccine safety monitoring programs around the world, closely monitors for specific adverse events known as ‘adverse events of special interest’. This close monitoring helps us to confirm the safety profile of COVID-19 vaccines, particularly with respect to possible side effects that may occur rarely. We conduct analyses to compare the number of reports of these events against the expected rate of events.

Adverse events of special interest reported for the AstraZeneca COVID-19 vaccine were:

• Anaphylaxis (22 reports)
• Seizure (6 reports)
• Loss of sense of taste or small (5 reports)
• Bleeding disorder (2 reports)
• Facial weakness (1 report)
• Joint infection (1 report)

Anaphylaxis is a very rare side effect that may occur with any vaccine. Only one of these reports meets the case definition criteria for anaphylaxis. The rate of confirmed anaphylaxis is consistent with what is expected for vaccines in general in Australia and internationally. The approved Product Information for the AstraZeneca COVID-19 vaccine has recently been updated to indicate that anaphylaxis has been observed in post-marketing experience.

Routine vaccination procedures include keeping people under observation for 15 minutes after vaccination and having appropriate medical treatment on hand so that anaphylaxis can be rapidly managed, if it occurs. A second dose should not be given to those who have experienced anaphylaxis to the first dose.

Seizures and joint infections are being monitored because of a theoretical link with vaccines. Facial weakness has been reported rarely in clinical trials for AstraZeneca COVID-19 vaccine. They can also occur around the time of immunisation for reasons not related to the vaccine. The number of reports of seizures, joint infections and cases of facial weakness received in Australia is no higher than the expected background rate in Australia. We are continuing to monitor these events closely.

The loss of sense of taste or smell is being monitored because of a theoretical link with COVID-19 disease. It may also be a non-specific symptom associated with feeling unwell. Our review does not suggest an increased risk of this with the AstraZeneca COVID-19 vaccine.

Close monitoring of adverse events involving blood clots

We have received two reports of blood clots for the AstraZeneca COVID-19 vaccine in Australia during the reporting period to 28 March 2021. These reports were of blood clots in the veins (also called venous thromboembolism), which are common conditions that occur in around 50 Australians every day. The number of reports received that relate to these common blood clots is no higher than the expected background rate in Australia.

We are carefully reviewing any Australian reports of possible blood clots following vaccination with the AstraZeneca COVID-19 vaccine to determine whether they may be similar to cases involving blood clots with very low platelets (thrombocytopenia) reported in Europe and the United Kingdom (UK). In some cases, this involves asking for extra information from the person who reported the event. To date, there is one report of a blood clotting disorder that appears similar to cases reported overseas. The TGA convened a Vaccine Safety Investigation Group (VSIG), comprising experts in vaccine safety, blood disorders, immunology, gastroenterology, infectious diseases, public health and vaccine confidence, to assess this case. On the basis of the information available at the time, the VSIG concluded that the case may be a new vaccine-linked event but there is insufficient definitive evidence to confirm the case was caused by the vaccine because there is not yet a body of evidence to conclusively establish a causal link, or for an alternative explanation. This conclusion will be reviewed as further information becomes available.

The Australian Technical Advisory Group on Immunisation has published an updated statement about this issue, with links to targeted advice for consumers and health professionals. This advice includes information about symptoms that might prompt further action (such as seeking medical attention).

The TGA is attending meetings with international medicines regulators this week about the investigations into cases reported in the UK and Europe. We will provide more information about the outcomes of the investigations when these are available.

Further information about the AstraZeneca COVID-19 vaccine can be found in the Consumer Medicine Information.

Active surveillance

AusVaxSafety is an active vaccine safety surveillance system that complements the TGA’s enhanced safety surveillance activities. Active vaccine safety surveillance uses SMS and a short survey to collect reports of AEFI directly from a subset of people receiving the vaccines. AusVaxSafety is an Australian Government-funded system that shares its findings with the TGA to assist our safety investigations and responses.

See details of AusVaxSafety’s latest COVID-19 vaccines safety data.

The AusVaxSafety findings support the TGA’s assessment that the COVID-19 vaccines used in Australia meet safety standards.

Other TGA safety information

During the past week, the TGA has published the following COVID-19 safety-related information:

• Statement by Acting Australian Government Chief Medical Officer, Professor Michael Kidd and Head of the Therapeutic Goods Administration Adjunct Professor John Skerritt  – 2 April 2021
  Australia's vaccine safety and regulatory process is world class and people can be confident that vaccines approved for use are safe and effective. Our vaccines will save lives and are an essential part of tackling this global pandemic.
• Specific clotting condition reported after COVID-19 vaccination – 2 April 2021
  Some rare cases of thrombosis associated with thrombocytopenia have been reported overseas following the administration of COVID-19 Vaccine AstraZeneca. The TGA has received one report of a case of thrombosis involving abdominal blood vessels and thrombocytopenia with symptom onset 7 days following COVID-19 Vaccine AstraZeneca in Australia.

Useful links

TGA COVID-19 vaccines hub

Australian Government Department of Health COVID-19 vaccines hub

AusVaxSafety