AstraZeneca’s COVID-19 vaccine is making headlines again, with European drug regulators poised to deliver verdict on possible links between the injection and rare blood clots in a small number of recipients.
The European Medicines Agency (EMA) is expected to make the announcement during a briefing scheduled for Wednesday at 14:00 GMT.
Several European countries have stopped using the vaccine in young adults because of blood clotting problems.
The EMA has previously said that AstraZeneca’s shot, which was developed jointly with the University of Oxford in the UK, is safe and its benefits outweigh any risks.
Further doubts about the vaccine would be a setback for the vaccine, which is essential for Europe’s vaccination campaign and a pillar of the global strategy to get vaccines to the poorest countries.
The vaccine is cheaper and easier to use than competing offerings from Pfizer-BioNTech and Moderna and has been approved for use in over 50 countries.
But inconsistent advice in some countries on who can take the vaccine has already raised fears that AstraZeneca’s credibility is permanently damaged, causing more reluctance to vaccinate and prolong the pandemic.
With that in mind, here’s what you need to know:
What are the latest fears about the vaccine?
AstraZeneca’s COVID-19 vaccine has been rolled out on a roller coaster, with early concerns the shot could be linked to unusual blood clots and abnormally low platelet levels in some young adults receiving it.
The EMA probe focused on 62 case reports of an extremely rare clot in the brain, known as cerebral venous sinus thrombosis (CVST), in recipients around the world.
This includes 44 cases out of 9.2 million people who received the vaccine in the European Economic Area, which includes European Union member states and Iceland, Liechtenstein and Norway.
The total cited by the EMA does not include all of the cases of the disease that have been reported in Germany, where 31 CVSTs have been recorded among the 2.7 million people vaccinated there. Most of the cases have affected young or middle-aged women. Nine people died.
In the UK, the country’s Independent Medicines and Healthcare Regulatory Agency (MHRA) has confirmed that seven people have died from blood clots after receiving the AstraZeneca vaccine.
Overall, the agency identified 30 cases of rare blood clots out of 18.1 million doses of the vaccine administered until March 24 inclusive.
He said he was undertaking a “rigorous review” of the reports, but urged people to keep taking the AstraZeneca vaccine.
How did the countries react?
Some countries, including Canada, France, Germany and the Netherlands, have suspended use of the vaccine in young adults while investigations continue.
Denmark and Norway have completely halted the deployment of fire.
Several other countries continued to use the vaccine without any restrictions, including the UK and Australia.
The British University of Oxford, however, on Tuesday suspended a trial testing the vaccine in children and adolescents pending further data.
What have regulators said so far?
The EMA, World Health Organization, MHRA and many other health authorities have repeatedly stated that the AstraZeneca vaccine is safe and effective and that the protection it offers against COVID-19 outweighs small risks of rare blood clots.
Last week, the European medicines regulator said there was “no evidence” that would support restricting the use of this vaccine in any population.
AstraZeneca pointed out that its own studies have found no higher risk of clots due to its vaccine.
But earlier this week, a senior EMA official said there was a causal link between the AstraZeneca vaccine and the few cases of rare blood clots.
“It is becoming increasingly difficult to assert that there is no cause and effect relationship between AstraZeneca vaccines and the very rare cases of blood clots associated with low platelet count”, Marco Cavaleri, manager threats to health and vaccine strategy to the Amsterdam-based agency, Roman newspaper Il Messaggero told Tuesday.
However, he also pointed out that the risk-benefit analysis remains positive for the AstraZeneca jab, even for young women who seem more affected by clots.