Use of Astra Zeneca’s COVID vaccine to be restricted in under 50’s due to rare clotting event, with GP’s advised to cancel bookings
The issues currently impacting Australia’s COVID-19 vaccine program have continued with new advice to restrict the use of the AstraZeneca vaccine in people aged under 50 years.
The AZ vaccine should “only be used in adults aged under 50 where the benefits clearly outweigh the risk for that individual and the person has made an informed decision based on an understanding of the risks and benefits”, the Department of Health has advised.
“People who have had the first dose of COVID-19 Vaccine AstraZeneca without any serious adverse effects can be given the second dose, including adults under 50 years”.
The advice follows a case of blood clotting which has been adjudged to be a “likely association” following administration of the vaccine.
In an updated safety advisory, the Theraupeutic Goods Administration said: “To date, one case of thrombosis with thrombocytopenia reported in Australia has been assessed by the Vaccine Safety Investigation Group (VSIG)”.
This independent expert advisory group 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”.
The TGA said it was “carefully reviewing all Australian reports of blood clots following the AstraZeneca vaccine, and are requesting further information from reporters where needed. Any further suspected case will be referred to the VSIG for assessment”.
In a communication sent to its “vaccine delivery partners”, the Department of Health says “In the short term, and in line with ATAGI’s recommendations, you may want to contact any patients under 50 who are currently booked to receive their first dose of the AstraZeneca COVID-19 vaccine and cancel in cases where the benefit clearly does not outweigh the risk“.
“By now you will be aware of advice provided by the Australian Technical Advisory Group on Immunisation (ATAGI) in light of the evolving evidence of a rare but serious side effect involving thrombosis with thrombocytopenia following receipt of the AstraZeneca vaccine,” the Department says.
“This ‘thrombosis with thrombocytopenia syndrome’ (TTS) is a newly described serious condition, with unusual blood clots in the brain (cerebral venous sinus thrombosis) or in other parts of the body, associated with low platelet levels and can cause serious long term disability or death.
“ATAGI has recommended new changes to the Australian COVID-19 Vaccine Program including a preference for the use of the Comirnaty (Pfizer) vaccine in adults aged under 50 years“.
In response, AstraZeneca said: “We respect the decision taken by the Australian Government based on advice from the Australian Technical Advisory Group on Immunisation (ATAGI) to recommend AstraZeneca’s COVID-19 vaccine be used in those over the age of 50.
Regulators around the world, including the Therapeutic Goods Administration (TGA), have reviewed the rare clotting events and did not identify any risk factors, such as age or gender, or a definite cause for these extremely rare events. However, they came to the view that these events have a possible link to the vaccine and requested they be listed as an extremely rare potential side effect”.
ATAGI’s statement provided further information on the advice:
- TTS remains an extremely rare event among vaccine recipients. Experience in Europe has shown approximately 4 – 6 people in every one million people develop TTS in the 4-20 days after the first dose of vaccine. However higher rates have been reported in some countries, and among younger people. One person in Australia developed the syndrome after receiving the AstraZeneca vaccine.
- The individual benefit-to-risk balance of vaccination with COVID-19 vaccine AstraZeneca in Australia varies with age. The risk of ongoing health issues and death from COVID-19 is highest in older age groups, particularly rising from 50 years of age. By comparison, the rate, and so possibility of disability and death from TTS may be higher in younger people.