In the UK, the Oxford-AstraZeneca vaccine has been approved for use, with the first doses due to be given soon amid rising coronavirus cases.
The government has ordered 100 million doses - enough to vaccinate 50 million people.
Health Secretary Matt Hancock said, this will cover the entire population, when combined with the full order of the Pfizer-BioNTech jab, 53,135 new Covid cases were recorded in the UK yesterday - the highest single-day rise since mass testing began - as well as 414 more deaths within 28 days of a positive test.
The steep rise in the cases comes in the wake of a new more infectious strain of the coronavirus is believed to have mutated in England's southeast which forced many nations to suspend flights from the UK.
Parts of England, including London, are under the strictest level of lockdown while Scotland and Wales have imposed restrictions over the holidays in a bid to stem the spread of the disease.