Surprise group risks vaccine side effect

As Australia’s first doses of locally manufactured AstraZeneca vaccine are rolled out, one group may be at risk of blood clots.

The first vials of AstraZeneca’s Australian-made COVID-19 vaccine were released on Wednesday marking a major milestone in the country’s vaccination program.

But experts this week accused the British-Swedish drug company of cherrypicking data in the latest release of figures about the vaccine’s effectiveness.

The use of the vaccine also continues to be blocked in some European countries due to concerns around blood clots.

So should Australians feel confident about getting the jab? Here is what we know.


The European Medicines Agency (EMA) investigated the AstraZeneca vaccine after a potential link to blood clots was raised. Last week it released its preliminary review.

In a somewhat confusing message, it said the vaccine was not associated with an increase in the overall risk of blood clots, but may be associated with clots linked to very rare condition involving low levels of blood platelets (thromocytopenia).

The agency pointed to how rare the cases were, with only 25 cases out of around 20 million people who had received the vaccine in the United Kingdom and European Union.

“A causal link with the vaccine is not proven, but is possible and deserves further analysis,” the agency said.

But last week two separate teams of medical researchers in Norway and Germany say they had found the vaccine could trigger an autoimmune reaction causing blood to clot in the brain, which could explain the rare cases.

The German researchers said that patients who show symptoms, such as headaches, dizziness or impaired vision, could be diagnosed with a blood test, so people shouldn’t be afraid of getting the vaccine.

“Very, very few people will develop this complication,” Greifswald University Clinic Professor Andreas Greinacher said in a press conference Friday. “But if it happens, we now know how to treat the patients.”

RELATED: Australia’s first locally manufactured AstraZeneca jabs rolled out


Analysis of nine deaths that occurred in Europe found most of these occurred in people under 55 and the majority were women. asked Health Minister Greg Hunt whether Australia would consider introducing blood tests to diagnosis those at risk, or would stop use of the AstraZeneca vaccine in people under 55, as France has done, and was referred to the Health Department, who provided a statement from Australia’s Therapeutic Goods Administration (TGA).

The TGA said it was closely monitoring the safety of the AstraZeneca COVID-19 vaccine and working closely with international regulators, through the International Coalition of Medicines Regulatory Authorities (ICMRA).

“We will continue to analyse any emerging information worldwide in relation to blood clots,” the TGA spokesperson said.

So far the TGA has not received any reports of blood clot cases in Australia after the use of the vaccine.

In its statement on the vaccine from March 19, the TGA noted a link to the vaccine had not yet been proved.

“It has not been proven that these cases were caused by the vaccine and a plausible mechanism for how they could have been caused by the vaccine has not been established,” the statement said.

“These conditions are also sometimes seen in people who have not received a COVID-19 vaccine or other vaccine.

“The EMA safety committee also noted that COVID-19 disease itself is often associated with serious clotting problems, which can themselves be fatal.”

The TGA noted that both European and UK regulatory agencies have said the benefits of the vaccine continue to outweigh the risk.

“The International Society on Thrombosis and Haemostasis also recommends that all eligible adults continue to receive COVID-19 vaccinations, even for patients with a history of blood clots or for those taking blood thinning medications,” it said.

RELATED: Your COVID vaccine questions answered


One of the crucial aspects of the vaccine is how effective it is and AstraZeneca is also facing controversy around its reporting of numbers.

AstraZeneca was accused this week by US medical experts of releasing “outdated” data and cherrypicking information to make its vaccine look better, in a letter The New York Times reported was sent to the company.

On Monday, AstraZeneca released its latest results from a trial carried in the US, Peru, and Chile, reporting an effectiveness of 79 per cent in preventing symptomatic COVID-19, and 100 per cent effectiveness against severe disease and hospitalisation.

But experts believe its effectiveness at preventing COVID-19 may actually be between 69 and 74 per cent.

The National Institute of Allergy and Infectious Diseases released a statement sharing concerns that AstraZeneca may have included outdated information from its initial trial, possibly providing an incomplete view.

AstraZeneca confirmed it had published data from an interim analysis using February numbers but vowed to release more data “within 48 hours”.

It said it had “reviewed the preliminary assessment of the primary analysis and the results were consistent with the interim analysis”.

“We are now completing the validation of the statistical analysis.”

NIAID head Anthony Fauci described the controversy as an “unforced error” by the company, while others warned it had the potential to erode public trust.

Experts have been quick to point out though, that the vaccine is performing well, and both levels of effectiveness were good.

Laureate Professor and Nobel laureate Peter Doherty of Australia’s Doherty Institute tweeted the results and said “both are good!”.

Infectious diseases expert Greg Dore of UNSW’s Kirby Institute tweeted: “Still think final results will confirm vaccine is very good, which we knew from earlier trials & real-world data”. | @charischang2

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