The European Commission on Monday authorized Pfizer and BioNTech’s coronavirus vaccine for conditional use, opening the door to an inoculation program across the European Union.

In a joint statement, the companies said they would begin delivering the vaccine doses immediately. In November, the European Commission struck a deal with Pfizer and BioNTech, securing 200 million doses in 2020 and 2021, with an option to obtain another 100 million doses.

The decision follows a nod from the European Medicines Agency, which had recommended granting conditional marketing authorization for the vaccine in people ages 16 years and over.

“EMA’s scientific opinion paves the way for the first marketing authorisation of a COVID-19 vaccine in the EU by the European Commission, with all the safeguards, controls and obligations this entails,” the agency said.

The news comes less than two weeks after the American and German-developed vaccine was approved for use in the U.S.

Europe is on track to start vaccinations within a week, regulators said, and authorities in several EU countries including France, Italy, Austria and Germany have said they aim to begin inoculations on Dec. 27.

The vaccine was first authorized in the U.K., which began its historic rollout on Dec. 7. It has proved 95% effective at preventing Covid-19 in late-stage clinical trials.

Vaccine authorizations are picking up pace just as European countries tighten their lockdowns amid a deadlier winter wave of virus infections.

A new and highly transmissible variant of the virus has been detected in the U.K., prompting Prime Minister Boris Johnson to mandate a strict lockdown for some areas. It has led to a mounting number of countries to suspend flights and transport links from Britain.

The coronavirus pandemic has killed nearly half a million people across Europe since it began.

Governments are struggling to implement effective strategies to both prevent further infections and keep local economies afloat as cases and deaths hit new records coming into the holiday season.

— CNBC’s Christine Wang contributed to this report.