Australia experts say ‘no indication’ AstraZeneca/Oxford vaccine linked to clots

Pharma News: Several European countries, including Germany and France, have now suspended use of the Oxford/AstraZeneca (AZ) vaccine after reports of blood clots. Queensland senator Matt Canavan has also called on Australia to pause its use of this vaccine.

Professor Bruce Thompson, Dean of the School of Health Sciences at Swinburne University, said “As of today in excess of 350 million vaccine doses have been given around the world. For those who have received the vaccine, there have been no deaths or hospitalisations due to COVID.

“This is an extraordinary result and credit to the outstanding scientists who are doing this work. As with any medication, there can be a hunch that there is a side effect. These hunches are important to follow up and the way drugs are regulated, especially in Australia with our TGA, they are.

“There has been a hunch that of the people who received the AZ vaccine, a few subsequently developed blood clots either as a DVT [deep vein thrombosis] or in their lungs. At this stage, there is no evidence at all that these are associated with being vaccinated. To stop a vaccination based on a hunch will lead to an increase in COVID deaths.”

Associate Professor Paul Griffin from University of Queensland and Director of Infectious Diseases at Mater Health Services commented “In my opinion, this response is an overreaction and while this is perhaps how these countries prefer to respond we should make sure we don’t overreact in our country and that we continue to make evidence-based decisions based on the available data at hand.

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“This vaccine has proven very safe and effective in large clinical trials. In fact in clinical trials now exceeding 60,000 participants some of these events were observed in low numbers but there were actually fewer in the vaccinated group than in those that had not received the vaccine.

“Available data from the use of this vaccine in the EU and UK now includes more than 17 million people vaccinated and has revealed only 15 events of DVT [deep vein thrombosis] and 22 events of PE [pulmonary embolism]. This is much lower than would be expected in a population of this size and is similar to other COVID-19 vaccines.

“What we know is that significant medical events such as these do occur and will keep occurring. Given we are now rolling out a vaccine globally in a short timeframe, by sheer chance some of these events will now occur in people who have been relatively recently vaccinated, however this relationship is coincidental, not causal. If this were not simply a coincidence we would have expected to see this occur in the clinical trials given their size and we would also expect the rates of these events to have increased in parallel with the roll-out of the vaccine, neither of these has occurred,” he added.

Associate Professor Nigel Crawford, Director of SAEFVIC (Surveillance of Adverse Events Following Vaccination in the Community), based at Murdoch Children’s Research Institute said “So far, data from the phase 3 clinical trials and real-world rollouts suggest blood clots and other ‘thromboembolic’ events occur no more frequently in people vaccinated with the AstraZeneca shot than they do in the general population. Thromboembolic events include blood clots, pulmonary embolisms and deep vein thrombosis.

“As vaccine safety experts, we agree it’s very important to investigate these safety concerns thoroughly. But we would urge extreme caution in pausing rollouts while investigations are underway, because once a vaccine rollout is paused, it can sometimes dent vaccine confidence so much that it struggles to recover, as seen in Japan with the Human Papillomavirus vaccine” he concluded.

According to a statement from the Therapeutic Goods Administration (TGA) “To 15 March 2021, the TGA has not received any reports of blood clots following administration of the AstraZeneca COVID-19 vaccine in Australia. There is no indication of an increased rate of blood clots happening or cause and effect with the AstraZeneca vaccine in Australia.”