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.
Airports in western Denmark reopened early on Thursday after being shut for hours when unidentified drones flew into their airspace overnight, the second such security incident in the Nordic country this week.
A Paris court found former French president Nicolas Sarkozy guilty of criminal conspiracy in a trial in which he was accused of receiving millions of euros in illegal financing from late Libyan dictator Muammar Gaddafi for his successful 2007 presidential bid.
Taiwan searched on Thursday for 33 people missing after a strong typhoon flooded a lake above a small town on its remote east coast, leading to a disaster as many victims were too elderly to follow evacuation guidance to go upstairs in their homes.
Security forces patrolled the streets on Thursday in India's Himalayan region of Ladakh, where curfew was clamped in some areas a day after four people were killed in violent protests demanding statehood for the federal territory and job quotas.