HomeNewsWorldEU agency to share results of probe into AstraZeneca shot

EU agency to share results of probe into AstraZeneca shot

Earlier this week, a senior official from the European Medicines Agency said there was a causal link between the AstraZeneca vaccine and the rare clots that have been seen in dozens of people worldwide, among the tens of millions who have received at least one dose of the shot.

April 07, 2021 / 19:03 IST
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AstraZeneca vaccine (Source: Reuters)
AstraZeneca vaccine (Source: Reuters)

The European Union’s drug regulator will announce the conclusions of its investigation into the possible connection between AstraZeneca’s coronavirus vaccine and rare blood clots later Wednesday, including recommendations that could have far-reaching effects on the use of the shot that is key to global efforts to end the pandemic.

Earlier this week, a senior official from the European Medicines Agency said there was a causal link between the AstraZeneca vaccine and the rare clots that have been seen in dozens of people worldwide, among the tens of millions who have received at least one dose of the shot.

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Marco Cavaleri, head of health threats and vaccine strategy at the Amsterdam-based agency, said in comments to Rome’s Il Messaggero newspaper on Tuesday that “it is becoming more and more difficult to affirm that there isn’t a cause-and-effect relationship between AstraZeneca vaccines and the very rare cases of blood clots associated with a low level of platelets.”
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But Cavaleri acknowledged the agency hadn’t yet figured out how exactly the vaccine might be causing these rare side effects. The agency said its evaluation “has not yet reached a conclusion and the review is currently ongoing.”
The EMA is particularly focused on two types of rare blood clots: one that appears in multiple blood vessels and another that occurs in a vein that drains blood from the brain. It is also evaluating reports of people who had low levels of blood platelets, which puts them at risk of severe bleeding.

The EMA, the World Health Organization and numerous other health authorities have said repeatedly that the AstraZeneca vaccine is safe and effective and that the protection it offers against COVID-19 outweighs the small risks of rare blood clots.

As recently as last week, the EMA said “there is no evidence that would support restricting the use of this vaccine in any population” — a response to several countries doing just that — though an expert said more brain clots were being reported than would be expected.

To date, most of the cases have been reported in younger women, who are more susceptible to developing such rare clots anyway, making understanding what is causing the clots potentially more difficult.

COVID-19 Vaccine
Frequently Asked Questions

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How does a vaccine work?

A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.

How many types of vaccines are there?

There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.

What does it take to develop a vaccine of this kind?

Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.
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