COVID-19 vaccine weekly safety report - 31-03-2021

Last week, the TGA received a total of 1546 AEFI reports for COVID-19 vaccines, including 496 for the Comirnaty vaccine, 1036 for the AstraZeneca COVID-19 vaccine, and 14 reports where the vaccine tradename was not reported. The most common adverse events reported for COVID-19 vaccines during this period, from most to least common, were:

• Headache
• Fever
• Muscle pain
• Chills
• Fatigue

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 21 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
• Dizziness
• Nausea
• Injection site reaction 
• Fatigue

The occurrence of these adverse events is consistent with what is already known about the Comirnaty vaccine. Headache, injection site reaction, nausea and fatigue 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 (18 reports)
• Facial weakness (5 reports)
• Seizure (5 reports)
• Stroke (2 reports)
• Pulmonary embolism (1 report)
• Deep vein thrombosis (1 reports)
• Loss of sense of taste (1 report)

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. Initial review of these cases indicates that at least 12 of the current cases do not meet the assessment 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 - external site. 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.

Facial weakness or paralysis has been reported rarely in clinical trials for Comirnaty. It can also occur around the time of immunisation for reasons not related to the vaccine. The number of reports of facial weakness received in Australia is no higher than the expected background rate in Australia. We are continuing to monitor these events closely.

Seizures 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 number of reports of seizures received in Australia is no higher than the expected background rate in Australia. We are continuing to monitor these events closely.

Stroke, pulmonary embolism, deep vein thrombosis and loss of sense of taste are being monitored because of a theoretical link with COVID-19 disease. The loss of sense of taste may also be a non-specific symptom associated with feeling unwell. Our review does not suggest an increased risk of these or any other adverse event of special interest associated with Comirnaty.

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

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 (9 reports)
• Seizure (2 reports)
• Loss of sense of taste (1 report) 

Anaphylaxis is a very rare side effect that may occur with any vaccine. We have reviewed the 9 reports of possible anaphylaxis for AstraZeneca COVID-19 vaccine and determined that only one of these reports met the assessment 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 of Comirnaty should not be given to those who have experienced anaphylaxis to the first dose.

Seizures are being monitored because of a theoretical link with vaccines. The loss of sense of taste 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 these adverse events of special interest associate with the AstraZeneca COVID-19 vaccine.

We have received no confirmed reports of blood clots for the AstraZeneca COVID-19 vaccine in Australia during the reporting period to 21 March. In light of cases of rare blood clotting disorders reported overseas, we are carefully reviewing any Australian reports of possible blood clots following vaccination to determine whether they are consistent with true blood clotting conditions and whether they may have been caused by the vaccine or related to background medical conditions. We are reviewing information from investigations conducted by overseas vaccine regulators, the vaccine sponsor and the World Health Organization. Further information on this issue can be found in the Australian Technical Advisory Group on Immunisation statement - external site.

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

Active surveillance

AusVaxSafety - external site 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 - external site.

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

Useful links

TGA COVID-19 vaccines hub

Australian Government Department of Health COVID-19 vaccines - external site hub

AusVaxSafety - external site