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EMA confirms AstraZeneca blood clots link

AstraZeneca Covid-19 Vaccine

The European Medicines Agency (EMA), has concluded that “unusual blood clots with low blood platelets should be listed as very rare side effects of Vaxzevria (formerly COVID-19 Vaccine AstraZeneca).” The review was conducted by the Pharmacovigilance Risk Assessment Committee (PRAC), the committee that is responsible for assessing all aspects of the risk management of medicines for human use. 

The EMA took into consideration all currently available evidence, which includes advice from an ad hoc expert group. Therefore the EMA is reminding healthcare professionals and people receiving the vaccine to remain aware of the possibility of blood clots combined with low levels of blood platelets. Deemed as very rare cases, these symptoms start occuring within 2 weeks of vaccinations. Current evidence shows that so far, most of the cases reported were women under 60 years of age within the 2 weeks of vaccination. Based on that evidence only, specific risk factors have not been confirmed. 

Therefore, people who have received the vaccine should seek medical assistance immediately if they develop symptoms of this combination of blood clots and low blood platelets.

The review was concluded on Wednesday 7th of April, however, a senior official at the EMA had already said that there is a clear “association” between AstraZeneca’s Covid-19 vaccine and very rare blood clots in the brain, though the direct cause of the clots is still unknown.

“In my opinion, we can now say it, it is clear that there is an association (of the brain blood clots) with the vaccine. However, we still do not know what causes this reaction,” said Marco Cavaleri, Head of Vaccines Strategy at the EMA.

The EMA also intervened on the 18th of March, following the suspension of the AstraZeneca vaccine in several countries to say that the benefits outweigh the risks.

“The committee came to a clear scientific conclusion: this is a safe and effective vaccine. Its benefits in protecting people from Covid-19, with the associated risks of death and hospitalization, outweigh the possible risks,” said the EMA Executive Director Emer Cooke 

Though the PRAC concluded that there was a link between the blood clots and the vaccine, it also shared the same stand that the benefits outweigh the risks. 

“COVID-19 is associated with a risk of hospitalisation and death. The reported combination of blood clots and low blood platelets is very rare, and the overall benefits of the vaccine in preventing COVID-19 outweigh the risks of side effects.” concluded the report of the PRAC

The PRAC also reported that “one plausible explanation for the combination of blood clots and low blood platelets is an immune response, leading to a condition similar to one seen sometimes in patients treated with heparin (heparin induced thrombocytopenia, HIT).”

The PRAC has therefore requested new studies and amendments to ongoing ones to provide more information and will take any further actions necessary.

After the EMA reported the link between blood clots and the vaccine, Spain and Italy decided to limit the use of the AstraZeneca vaccine to people aged above 60, while Belgium restricted the vaccine to those aged 56 or older for a minimum of four weeks. Australia in turn decided to limit further use of the vaccine in people younger than 50 years old and to use BioNTech/Pfizer for inoculations.

France and Germany had previously restricted the use of the AstraZeneca shot for over 55 years old and over 60 years old respectively, trusting that other vaccines such as BioNTech/Pfizer and Johnson&Johnson one shot vaccine would suffice to bridge the lag in the EU’s vaccination programme. 

As for the UK, it abruptly changed its guidance over the AstraZeneca vaccine on Wednesday, now recommending that people aged between 18 and 29 are offered alternative vaccines. Sweden and Finland is allowing its use only for people above 65 years old, while Denmark and Norway suspended the use of AstraZeneca until at least next week. 

As for Mauritius, around 100,000 of Mauritians already obtained the first dose of the AstraZeneca vaccine and are preparing to administer the second dose. No cases of blood clots, or low blood platelets were reported.