Tuesday, August 3

Why some countries have discontinued the AstraZeneca vaccine and what it means for Australia: explanation | Health


Several European countries, including Norway, Denmark, the Netherlands and Ireland, have temporarily suspended the launch of the AstraZeneca vaccine due to concerns about deep vein thrombosis, pulmonary embolism and blood clotting. Meanwhile, Italy, Austria, Estonia, Latvia, Luxembourg and Lithuania have suspended inoculations of a particular batch of 1 million doses that was shipped to 17 countries.

Vaccination programs with the AstraZeneca vaccine continue in other countries, including the UK and France. The UK is encouraging people to keep getting vaccinated.

According to AstraZeneca, there have been 15 cases of deep vein thrombosis and 22 events of pulmonary embolism among more than 17 million vaccinated people in the European Union and the United Kingdom.

In Australia, the prime minister and health minister have said there are no plans to stop the launch. So should Australians be concerned?

What are deep vein thrombosis and pulmonary embolism?

Sometimes blood clots can form in a blood vessel, often in the leg due to reduced circulation which can be a problem in the lower extremities. When these clots develop, whether in the lower leg, thigh, pelvis, or arm, the condition is known as deep vein thrombosis.

If one of these blood clots breaks loose and travels, they can lodge in a blood vessel and block the blood supply to an organ. When this blockage occurs, it is called an embolism. Anything “pulmonary” is related to the lungs, so a pulmonary embolism occurs when the blood clot, or embolism, blocks one of the arteries that lead from the heart to the lungs.

This is serious and life-threatening because it can affect oxygen levels in the lungs and cause lung damage. Symptoms can include dizziness, chest pain, shortness of breath, and cough.

The best way to avoid blood clotting and these related conditions is to maintain a healthy weight, stay active, stay hydrated with water, avoid smoking, and avoid sitting for long periods of time.

Is the AstraZeneca vaccine causing these problems?

According to an AstraZeneca statement issued Monday, the rate of deep vein thrombosis and pulmonary embolism among the millions of people vaccinated is “much lower than would be expected to occur naturally in a general population of this size and is similar in other Covid. authorized. -19 vaccines “.

AstraZeneca Medical Director Ann Taylor said: “The nature of the pandemic has led to increased attention in individual cases and we are going beyond standard practices for monitoring the safety of licensed drugs by reporting vaccine events. , to guarantee public safety “.

He said that in terms of quality, there were no confirmed problems related to any batch of vaccine used in Europe or the rest of the world. The company is conducting additional tests, but also independently by the European health authorities.

As of Monday, none of these new tests have proven to be a cause for concern.

What have Australian regulators said?

Australia’s drug regulator, The Therapeutics Administration (TGA), said a link between blood clots and the AstraZeneca vaccine has not been confirmed.

“As of March 11, 2021, the TGA has received no reports of blood clots after the use of the AstraZeneca vaccine in Australia,” said the TGA. “Extensive international experience does not indicate an increased risk of blood clots associated with the vaccine. Blood clots can occur naturally and are not uncommon. “

Prime Minister Scott Morrison said the TGA conducts its own batch tests of the vaccines and also analyzes data from abroad. Australia’s chief medical officer, Professor Paul Kelly, said that “safety is our first priority and in a large vaccine launch like this we must carefully monitor any unusual events to find it.”

“This does not mean that all post-vaccine events are caused by the vaccine,” he said.

“But we took them seriously and investigated.”

What do scientists and experts say?

Emeritus Professor Gerard Fitzgerald, a public health specialist at Queensland University of Technology, said countries that suspended the launch of the AstraZeneca vaccine had acted “with extreme caution.” But it was important to remember that blood clots are extremely common, and they were before vaccines existed.

“For example, the CDC [Centers for Disease Control and Prevention] in the US it reports 60 to 100,000 deaths per year from blood clots in the lungs, ”Fitzgerald said.

“These are more common again in the elderly and those with chronic illnesses who are the people who are the target of early vaccination programs. We must also take into account any risks. So far, more than 2.5 million people have died from Covid-19 and between 8,000 and 10,000 people die every day around the world. More than 320 million people have already been vaccinated worldwide.

“Scientifically conducted clinical trials of the vaccines prior to their approval did not identify any increased risks associated with the vaccine.”

Is the safety data transparent?

Yes. The monthly safety report for the AstraZeneca vaccine will be made public on the European Medicines Agency website the following week, according to exceptional transparency measures for Covid-19.

Blood clots are considered “adverse events of special concern”, which are closely monitored in Australia and by foreign regulators. The TGA works closely with international regulators and shares information about the safety of the Covid-19 vaccine. If the TGA detects a security issue, it is committed to taking swift action to address it and provide information to the public.

Consumers and healthcare professionals are encouraged to inform problems with medications or vaccines to the TGA.

Professor Julie-Anne Leask, from the Susan Wakil School of Nursing and Midwifery at the University of Sydney, is a social scientist whose research focuses on infectious diseases and immunization controversies and communication.

Leask said that once an adverse event is detected, regulators and vaccine safety experts will investigate whether the event is believed to be caused by the vaccine.

“This is a normal part of any vaccine program,” he said. “It shows that a system is open, transparent and responsive. Governments want to make sure they are giving people safe vaccines. ”


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