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 ship with humanitarian aid and activists for Gaza was bombed by drones while in international waters off Malta early on Friday, its organisers said, and the Maltese government said after a rescue operation that everyone on board was safe.
A power outage hit several regions of Indonesia's resort island of Bali on Friday and efforts were underway to restore services to those affected, state utility Perusahaan Listrik Negara said.
A Russian drone attack late on Thursday set buildings ablaze in Ukraine's southeastern city of Zaporizhzhia, injuring 29 people, regional governor Ivan Fedorov said.
Israel attacked a target near the presidential palace in the Syrian capital Damascus, Israeli Prime Minister Benjamin Netanyahu said early on Friday, reiterating his vow to protect members of the Druze community.
South Korea's top court cast doubt on Thursday on frontrunner Lee Jae-myung's eligibility to run for the presidency, while the resignations of the prime minister and finance minister shook the interim government in place since December's martial law.