Review of the COVID-19 vaccine from AstraZeneca

The Danish Health Authority has suspended the use of Vaxzevria, the COVID vaccine from AstraZeneca, for five weeks until week 15, while the review of the future use of the vaccine in the Danish vaccination programme against COVID-19 is still ongoing.

At the end of March 2021, the European Medicines Agency (EMA) convened an ad hoc expert group to provide input to its safety committee’s – The Pharmacovigilance Risk Assessment Committee (PRAC) – review into the rare cases of blood clots in people who received the COVID-19 vaccine from AstraZeneca. EMA announced the conclusion of the review of PRAC on Wednesday. EMA concludes that there is a possible link between rare cases of unusual blood clots with low blood platelets and the COVID-19 vaccine from AstraZeneca. Further, EMA is reminding healthcare professionals and people receiving the vaccine to remain aware of the possibility of developing symptoms within two weeks of vaccination. EMA’s assessment remains that the overall benefits of the vaccine in preventing COVID-19 outweigh the risks of side effects.

"EMA’s review proves that it was imperative to examine the possible correlation between the vaccine and the blood clots and confirms that we demonstrated due diligence in suspending the use of the vaccine in Denmark while the vaccine is undergoing further research analysis and studies. We are waiting to get the Danish results too, and expect to announce our findings next week based on the latest scientific evidence," says Director General Søren Brostrøm.

A range of national measures have been launched to investigate the possible link between the COVID-19 vaccine from AstraZeneca and the rare but severe blood clotting events, bleeding, and low blood platelet counts.

To strengthen the professional dialogue between health authorities and experts, the Danish Health Authority has convened a group of Danish experts from a range of medical specialities, including anticoagulant medicine, immunology, neurology, infectious medications, and pharmacoepidemiology. The national expert group is involved in the ongoing Danish research, including registry studies, research under the auspices of ENFORCE (the extensive Danish study of the rollout of the COVID-19 vaccines) and clinical laboratory research. This group of experts also gives advise to the Danish Health Authority.

The Danish Health Authority decided to suspend vaccination with the vaccine from AstraZeneca, pending results from these ongoing studies and EMA’s announcement.

However, the risk among those Danes who have already been vaccinated with the COVID-19 vaccine from AstraZeneca ought to be over at this time.

"We can see that the risk of the severe side effects associated with the vaccination is expected to be highest within about 7-10 days, significantly reduced after 14 days, and no severe blood clotting events have been reported after 21 days. Therefore, we estimate that those Danes who have already been vaccinated with the vaccine from AstraZeneca no longer have to worry about getting these rare side effects. At the same time, the first injection of the effective vaccine from AstraZeneca has already given approximately 150,000 Danes protection against COVID-19," says Søren Brostrøm.

Whether those who received the first injection with the vaccine from AstraZeneca will complete the vaccination programme with that vaccine – or one of the other available vaccines – depends on the final decision on the use of Vaxzevria. This decision awaits the outcome of EMA’s review and the conclusions from the national group of experts.