Britain on Wednesday became the first nation to approve the coronavirus vaccine developed by AstraZeneca and the University of Oxford, as Germany logged its highest daily death toll with the pandemic surging worldwide.
Fears have also grown following the detection in Britain of a new strain of the virus experts fear is more transmissible, and the variant has been found in a number of other countries, including the United States and India.
The pandemic prompted unprecedented global efforts to develop vaccines in record time, and following Pfizer-BioNTech and Moderna, the AstraZeneca-Oxford candidate became the third to win approval in the Western world.
"It is truly fantastic news," tweeted British Prime Minister Boris Johnson. "We will now move to vaccinate as many people as quickly as possible."
Unlike the Pfizer-BioNTech and Moderna vaccines, the one from AstraZeneca and Oxford does not need to be stored at very low temperatures. It can be kept, transported and handled at normal refrigerated conditions, making it easier and cheaper to administer and a much smaller logistical challenge, especially for less wealthy nations.
Russia and China also claim to have developed Covid-19 vaccines, and have already started administering them.
Chinese pharma giant Sinopharm on Tuesday said that Phase 3 trials of its candidate had shown 79 percent effectiveness, close to the more than 90 percent achieved by Pfizer-BioNTech and Moderna. The firm has applied to China's drug regulator for approval.
But Beijing has struggled to gain international trust for its vaccines, hindered by a lack of data transparency as well as criticism over its handling of the initial outbreak of the virus in the central Chinese city of Wuhan and its attempts to silence whistleblowers.
The number of infections in that city may have been 10 times higher than official figures suggest, according to a study by China's Centre for Disease Control.
- New variant worries -
Even as vaccinations ramp up in Europe and North America, global infections have surged close to 82 million, with nearly 1.8 million deaths.
Germany, which had handled the first coronavirus wave relatively well, has been hit hard by the second. It logged more than 1,000 daily deaths for the first time, authorities said Wednesday.
Fears have also grown with the recent detection in Britain of a virus variant experts believe could be more transmissible.
The variant has been detected in a number of other countries, after pushing Britain to a new daily record of infections.
Indian authorities were trying Wednesday to track down tens of thousands of people who arrived from Britain in recent weeks as cases of the new variant more than doubled in 24 hours.
The variant was detected for the first time in the United States and Latin America on Tuesday.
The EU health agency has warned the strain carried a high risk for more hospitalisations and deaths -- not because the infections are more severe but because it spreads more easily.
- 'Greatest operational challenge' -
In the United States -- the worst-hit nation in the world -- President-elect Joe Biden called mass vaccination "the greatest operational challenge we've ever faced as a nation".
The Trump administration had predicted that 20 million Americans would be vaccinated by the end of December. But with days left, just over two million have received the first shot of the vaccine, according to the Centers for Disease Control and Prevention.
Biden, who takes over from Donald Trump on January 20, renewed his promise to administer 100 million vaccine doses in his first 100 days in office, and confirmed he would invoke a Korean War-era law to force private industry to step up production.
"The Trump administration's plan to distribute vaccines is falling far behind," Biden said, promising: "I'm going to move Heaven and Earth to get us going in the right direction."
But he warned: "The next few weeks and months are going to be very tough -- a very tough period for our nation, maybe the toughest during this entire pandemic."