Italy, France, Germany and Spain plan to restart AstraZeneca vaccinations after the European Medicines Agency (EMA) concluded that the AstraZeneca COVID vaccine is "safe and effective".
A number of European countries had suspended the jab over unconfirmed reports of an increased rate of blood clots among recipients.
That prompted the EMA to launch a safety review to see if there was a link between the vaccine and the blood clots.
"Its benefits in protecting people from COVID-19 with the associated risks of death and hospitalisation outweigh the possible risks," EMA executive director Emer Cooke said at a press conference.
She qualified, however, that the regulator "cannot rule out definitively a link between these [blood clot] cases and the vaccine."
Following the EMA's announcement, Italy said it would restart its rollout of AstraZeneca vaccinations on Friday.
French government officials said they would do the same, with Prime Minister Jean Castex getting the vaccine on Friday afternoon to show government confidence in the jab.
Spain and Germany also announced that they would restart AstraZeneca vaccinations.
However, Norway, Sweden and Denmark said they would continue their suspension of the jabs while they reviewed the EMA verdict.
Vaccines 'help prevent death and hospitalisation', says EMA
Cooke said the safety review committee will continue their investigations into blood conditions related to vaccines.
"We have to continually remind ourselves what a difficult situation we're in. This pandemic is costing lives. We have vaccines that are safe and effective that can help prevent death and hospitalisation. We need to use those vaccines within the environments that we have them," Cooke said later on in the press conference.
The opinion of the EMA was hotly anticipated at a time when the European Union, in the midst of a vaccine shortage, is counting on millions of doses of this vaccine developed by British-Swedish firm AstraZeneca.
The World Health Organization has also said there is no evidence the vaccine is to blame.
Cooke previously said this was not an "unexpected" situation when millions of people are being vaccinated, and thousands develop blood clots each year.
"Our role at the EMA is to evaluate these, to make sure that any suspected adverse reactions are rapidly investigated so we can figure out, is this a real side effect to the vaccine or is it a coincidence," she said.
No evidence of blood clot causality but investigations to continue
The EMA committee "has concluded that there is no increase in the overall risk of blood clots with this vaccine," said Dr Sabine Straus, chair of the EMA safety review committee, adding that there was no evidence of a batch issue.
However, she said, there were a few cases where "tiny clots developed in multiple blood vessels in the first 7-14 days after vaccination," Straus said. There were also a few cases of clots in blood vessels draining blood from the brain, she added.
There were just seven cases of the tiny clots and eighteen cases of the other blood condition out of 20 million people vaccinated, according to EMA.
The safety committee said they recommended adding a warning with a description of these cases so healthcare professionals are made aware of the information and the signs and symptoms of concern.
Straus added however that "COVID itself is an important risk factor for thrombosis and also post-COVID syndrome we noted that often people are being hospitalised with thrombosis in the aorta. It might be that that might have played a role."
The rare cases were predominately found in younger women, Dr Straus said, but she added that it was too early to draw any conclusions about it. She confirmed that they were looking into any link to the contraceptive pill as it can increase a woman's chance of developing blood clots.
EU countries seek quick thaw
Even before Thursday's announcement by Europe's watchdog, the president of the European Commission made it clear that the AstraZeneca vaccine will remain a pillar of the EU’s vaccine strategy.
“I trust AstraZeneca, I trust the vaccines,” Ursula von der Leyen said.
Almost as soon as France’s president froze the vaccinations Monday, top French officials started worrying about the impact on public opinion in a country where many already viewed the AstraZeneca vaccine as second-class.
French Prime Minister Jean Castex said he would get the vaccine on Friday once the EMA safety review committee confirmed it was safe.
Italian Health Minister Roberto Speranza had said European countries were hoping that the EMA on Thursday would deliver "the clarifications and reassurances necessary" to be able to resume administering the AstraZeneca vaccine "without hesitation."
In Germany, where eight cases of blood clots are under investigation, officials defended the decision to suspend vaccinations pending further investigation but were also ready to resume them soon. Health Ministry spokesman Hanno Kautz said, “It’s clear that the EMA decision is binding, and of course we will follow the EMA decision too.”
Lithuania’s president criticised its health minister’s decision to suspend the shots, saying it causes "enormous damage to the entire vaccination process."
Amós García, president of the Spanish Vaccinology Association, said it will be difficult for governments to rebuild trust in the overall coronavirus vaccination programme, no matter what the EMA announces.
"The problem when a vaccine is put in doubt is not that it affects that vaccine, but that it affects the whole vaccination world," he said.
“Possibly there has been an excess of zeal” among governments like Spain’s that suspended vaccinations, he said. But he praised Europe's vaccine surveillance systems for quickly identifying and investigating the blood clot issues. Spain is examining three such cases.
Spanish Health Minister Carolina Darias defended the decision to put a hold on the AstraZeneca vaccine, saying it is necessary to “continue building confidence” in efforts to fight COVID-19.