The green light for Moderna Inc's vaccine from the European Medicines Authority (EMA), and later the European Commission, was a big boost for European hopes of containing a disease that has infected more than 85 million people globally and killed nearly 1.9 million.
"With the Moderna vaccine, the second one now authorized in the EU, we will have a further 160 million doses. And more vaccines will come," said Ursula von der Leyen, who heads the European Union executive.
The EMA granted conditional marketing approval two weeks ago for a similar vaccine from US company Pfizer Inc and German partner BioNTech SE.
The Pfizer/BioNTech vaccine has been given to hundreds of thousands of Europeans since roll-out began a week ago though the campaign has been uneven, with officials in Germany and France frustrated at the slow rate of progress.
The Moderna vaccine will help accelerate vaccination campaigns in Europe as concerns grow about two more infectious variants of the virus, detected in South Africa and Britain, which have driven a surge in cases..
Governments in many countries face growing public criticism for appearing slow to curb the spread of the virus, including the Netherlands, which started its vaccination drive a week after many other EU member states.
Sanna Elkadiri, a 39-year-old nurse who looks after dementia patients at a care home in the south of the country, received a shot of the Pfizer/BioNTech vaccine.
"This is the beginning of the end of this crisis," Health Minister Hugo de Jonge said at a brief ceremony.
Dutch Prime Minister Mark Rutte said his government had been preparing for a vaccine developed by Oxford University and AstraZeneca to be approved first, and this had reduced the Dutch authorities' flexibility.
TEST FOR EUROPE
The vaccine roll-out has been a test of Brussels' ability to unify Europe amid political pressure to speed up the process.
Some EU member states fretted over the length of time the EMA took to decide on the Pfizer-BioNTech shot, leaving it lagging the United States, Britain, Israel and Switzerland in approving and administering the first vaccines.
The regulator has given conditional marketing approval - rather than the ultra-fast emergency use approval issued by Britain, saying more detailed study of the data is required.
The European Commission defended its actions, saying it had been important not to put all its eggs in one basket when various vaccines were still at development stage.
"We always knew that it would be a complex operation and this is precisely why the European Commission was so adamant that it was important we could sign contracts with different companies," spokesman Eric Mamer said.
The two-dose Moderna vaccine - which can be stored and transported more easily than the Pfizer-BioNTech vaccine - has already been rolled out in the United States and Canada, and Israel this week granted authorisation.
It was about 95% effective at preventing illness in clinical trials that found no serious safety issues.
With COVID-19 cases continuing to surge worldwide, the World Bank has warned that rising infections and delays in vaccine distribution could limit the global economic recovery to growth of just 1.6% this year.
GOVERNMENTS UNDER FIRE
More people in the United States are now hospitalized with COVID-19 than at any time since the global pandemic began, according to a Reuters tally of public health data, and state and local officials face growing pressure to speed up vaccine distribution.
China, where the first cases of the novel coronavirus were identified in December 2019, on Wednesday imposed travel restrictions and banned gatherings in the capital city of Hebei province, which surrounds Beijing.
Although Britain was the first country to approve and start administering the Pfizer/BioNTech vaccine, Prime Minister Boris Johnson's government has been accused by political opponents of indecision after England began a new lockdown this week.
The French government has come under fire after its inoculation campaign began slowly, hampered by red tape and President Emmanuel Macron's decision to tread warily in one of the world's most vaccine-skeptical countries.
France is now stepping up its vaccine roll-out and experts say a third national lockdown should be ruled out.
Germany has decided to extend a nationwide lockdown until the end of this month and to introduce tougher restrictions. But Finance Minister Olaf Scholz said Europe's biggest economy could hold out for a long time.