COVID-19 vaccine weekly safety report - 14-04-2021

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 5 April - 11 April 2021

Last week, the TGA received a total of 2387 AEFI reports for COVID-19 vaccines, including 503 for the Comirnaty vaccine, 1862 for the AstraZeneca COVID-19 vaccine, and 22 reports where the vaccine tradename was not reported. The most common adverse events reported for COVID-19 vaccines during this period were:

• Headache
• Muscle pain
• Fever
• Fatigue
• Chills

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 4 April 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
• Muscle pain
• Nausea
• Fatigue
• Fever

The occurrence of these adverse events is consistent with what is already known about the Comirnaty vaccine and with AusVaxSafety active surveillance data. Headache, muscle pain, injection site reaction, nausea, fatigue and fever 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 (39 reports)
• Bleeding disorder (11 reports)
• Facial weakness (6 reports)
• Seizure (7 reports)
• Cardiac event (3 reports)
• Loss of sense of taste or smell (3 reports)
• Liver injury (1 report)
• Muscle damage (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. Review of these cases indicates that only 14 meet the case definition criteria for anaphylaxis. The patients were described as recovered or recovering at the time of reporting in most cases, and there have been no reports of associated deaths. 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.

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 appear related to the more common type of blood clot conditions that can occur in around 50 Australians every day separate to vaccination. The overall number of reports received is no higher than the expected background rate for the more common type of blood clots in Australia. These are not related to the very rare 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. These can also occur around the time of immunisation for reasons not related to the vaccine. The loss of sense of taste or smell, muscle damage and liver injury are being monitored because of a theoretical link with COVID-19 disease. The loss of taste or smell may also be a non-specific symptom associated with feeling unwell. Our review does not suggest an increased risk of any of these adverse events of special interest above the background population rate with the Comirnaty vaccine.

Further information about Comirnaty can be found in the Consumer Medicine Information - external site (for consumers) and Product Information - external site (for health professionals).

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 and with AusVaxSafety active surveillance data. 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 (30 reports)
• Bleeding disorder (11 reports)
• Seizure (12 reports)
• Loss of sense of taste or small (6 reports)
• Facial weakness (2 reports)
• Rare skin rash (1 report)

Anaphylaxis is a very rare side effect that may occur with any vaccine. Only three of these reports meets the case definition criteria for anaphylaxis. The patient was described as recovered or recovering at the time of reporting in most cases, and there have been no reports of associated deaths. 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 facial weakness 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 and 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, and a rare skin rash known as erythema multiforme are 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 received 10 reports of blood clots for the AstraZeneca COVID-19 vaccine in Australia during the reporting period to 4 April 2021. These reports were of blood clots in the veins (also called venous thrombosis or venous thromboembolism). These reports are being investigated to see if they are related to the more common type of blood clot conditions that can occur in around 50 Australians every day separate to vaccination. The overall number of reports received is no higher than the expected background rate for the more common type of blood clots in Australia.

In light of emerging evidence for a possible link between the vaccine and rare and unusual clotting disorders, the approved Product Information - external site and Consumer Medicine Information - external site documents for the AstraZeneca COVID-19 vaccine now include warnings about thrombosis with thrombocytopenia. ATAGI has issued updated advice about this issue.

Healthcare professionals should be alert to the signs and symptoms of thromboembolism and thrombocytopenia as well as coagulopathies. Vaccinated individuals should be instructed to seek immediate medical attention if they develop symptoms such as a severe or persistent headache, blurred vision, shortness of breath, chest pain, leg swelling, persistent abdominal pain or unusual skin bruising and/or petechia a few days after vaccination.

We are carefully reviewing any Australian reports of possible blood clots following vaccination with the AstraZeneca COVID-19 vaccine to identify any further possible cases of this disorder to better characterise this potential risk, which is now referred to as ‘thrombosis with thrombocytopenia syndrome’ (TTS). This week the TGA convened an expert Vaccine Safety Investigation Group (VSIG) meeting to assess a second possible case of TTS in Australia. The VSIG concluded the case is likely to be linked to vaccination.

The TGA is continuing to attend meetings with international medicines regulators about ongoing investigations into this issue. The UK regulator (MHRA) has concluded that the evidence of a link with COVID-19 Vaccine AstraZeneca is stronger but more work is still needed. The European Medicines Agency has found that there is a possible link between the AstraZeneca COVID-19 vaccine and these cases.

There was one report of bleeding disorder related to low platelets with no associated blood clot. This was assessed as not being related to the blood clot issue.

Further information about the AstraZeneca COVID-19 vaccine can be found in the Consumer Medicine Information - external site (for consumers) and Product Information - external site (for health professionals).

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.

Other TGA safety information

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

• AstraZeneca ChAdOx1-S COVID-19 vaccine: Second case of thrombosis with thrombocytopenia – 13 April 2021
  A Vaccine Safety Investigation Group (VSIG), a panel of expert advisors convened by the TGA, has concluded that a recently reported case of thrombosis with thrombocytopenia is likely to be linked to vaccination. This is the second Australian report of a case of thrombosis with thrombocytopenia following the AstraZeneca COVID-19 vaccine. The case occurred in a woman in her 40s who was vaccinated in Western Australia. She remains in hospital receiving treatment and is in a stable condition.
• AstraZeneca ChAdOx1-S COVID-19 vaccine: Updated safety advisory – rare and unusual blood clotting syndrome (thrombosis with thrombocytopaenia) – 9 April 2021
  To date, one case of thrombosis with thrombocytopenia reported in Australia has been assessed by the Vaccine Safety Investigation Group (VSIG). The VSIG is an independent expert advisory group comprising experts in vaccine safety, public health, vaccine confidence and relevant medical specialists in blood disorders, immunology, gastroenterology, infectious diseases, convened by the TGA to assess such cases. The VSIG concluded that, based on available data, there was insufficient evidence to firmly confirm that the clot was caused by the vaccine, but emerging evidence suggests a likely association. However, this conclusion will be reviewed as further information becomes available.
• Wider storage and transportation conditions for the Pfizer COVID-19 vaccine now approved – 8 April 2021
  The TGA has recently approved wider storage and transportation conditions for the Pfizer COVID-19 vaccine in Australia (COMIRNATY - BNT162b2). These changes will enable greater flexibility in storage, transport and deployment of the Pfizer COVID-19 vaccine across Australia.

Useful links

TGA COVID-19 vaccines hub

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

AusVaxSafety - external site