Over a dozen European countries are set to restart the roll-out of the Oxford-AstraZeneca Covid-19 vaccine after Europe’s top drug regulator concluded it’s “safe and effective” — dismissing fears about blood clotting associated with the vaccine. Vaccination had been suspended across Europe following reports of a small number of cases of dangerous blood clots of people who recently received the vaccine.

The European Medicines Agency (EMA) reviewed millions of cases and found the vaccine doesn’t increase the overall risk of clots, although “there are some uncertainties,” said Sabine Straus, who leads the agency’s risk assessment committee, in a press conference. That’s why a warning label will be added to the vaccine so the medical community can be on the lookout.

The officials said they hoped that their statement on the safety of the vaccine will calm governments and their populations. Now it’s up to individual countries to decide whether and when to re-start vaccinations using the AstraZeneca vaccine. Germany, Italy, France, and Spain have already said they would resume using it very soon, while Sweden and Norway said they will await further study.

“Its benefits in protecting people from Covid-19 with the associated risks of death and hospitalization outweigh the possible risks,” Emer Cooke, the head of the European regulator, said in a press conference. “If it was me, I would be vaccinated tomorrow. But I would want to know that if anything happened to me after vaccination what I should do about it and that’s what we’re saying today.”

Days before EMA’s statement, the World Health Organization (WHO) had argued there’s no link between the AstraZeneca vaccine and blood clotting in patients. “There is no evidence that the incidents are caused by the vaccine and it is important that vaccination campaigns continue so that we can save lives and stem severe disease from the virus,” the WHO said in a statement.

About 20 million people in Europe have already received the AstraZeneca vaccine and suffered no serious side effects, EMA officials said. Still, they acknowledged that there were a limited number of cases of cerebral venous thrombosis – blood clots in the brain – in patients who also had low platelet counts. But the evidence isn’t conclusive as to whether this is related to the vaccine or not.

Researchers have argued the pause in the vaccination could further erode confidence in the AstraZeneca vaccine, which was already a focus of controversy due to confusing initial trial results, or in Covid-19 vaccines in general. In a preprint, researchers found vaccine confidence dropped 11% in Denmark following the government’s decision to suspend vaccination.

Still, EMA’s review came as a relief to many public health experts, who were worried about long delays in the COVID-19 vaccination programs at a time when cases are increasing in much of Europe. A variant of the virus that first emerged in the UK, known as B.1.1.7, seems to be the common culprit behind the current chaos, as it’s more easily transmitted from person to person.

Italy has reimposed lockdowns in an attempt to limit outbreaks, while more people are on ventilators in hospitals in Poland than at any time since the start of the pandemic. French President Emmanuel Macron said the country is “living through the hardest weeks now” and decided to implement a month-long limited lockdown for Paris and other regions of the country.