AstraZeneca said on Monday its vaccine for the novel coronavirus, developed along with the University of Oxford, could be around 90 per cent effective under one dosing regimen.
"This vaccine's efficacy and safety confirm that it will be highly effective against COVID-19 and will have an immediate impact on this public health emergency," Pascal Soriot, Astra's chief executive, said in a statement.
British Health Secretary Matt Hancock described as "fantastic news".
"These figures... show that the vaccine in the right dosage can be up to 90 per cent effective," he told Sky News, after an announcement from AstraZeneca.
"We've got 100 million doses on order and should all that go well, the bulk of the rollout will be in the new year."
The British drugmaker's preliminary trial results mark a fresh breakthrough in the fight against a pandemic that has killed nearly 1.4 million people and roiled the global economy.
A US immigration agent has shot and killed a 37-year-old woman in her car in Minneapolis on Wednesday during an immigration enforcement surge, according to local and federal officials, the latest violence in President Donald Trump's nationwide crackdown on migrants.
Israel's military said on Thursday it had carried out a targeted strike on a rocket launch site near Gaza City after identifying a failed launch, as questions mount over when the next phase of the Gaza ceasefire will begin.
Laurent Vinatier, a French researcher serving a three-year prison sentence in Russia for violating Moscow's foreign agent laws, has been freed as part of a prisoner exchange, French and Russian officials said on Thursday.
The US has seized two Venezuela-linked oil tankers in the Atlantic Ocean on Wednesday, one sailing under Russia's flag, as part of President Donald Trump's aggressive push to dictate oil flows in the Americas and force Venezuela's socialist government to become an ally.
Ukrainian officials were racing to restore power on Thursday after Russian strikes plunged two southeastern regions into near-total blackout overnight, forcing critical infrastructure to rely on reserves.