He tweeted: " As the year closes and people around the world raise a toast to mark both the passing of the year and the dawn of a new one, I raise a toast to science; may we share its results (vaccines) fairly and equitably in the year ahead and together end the #COVID19 pandemic! #ACTogether."

He said: "There will be set backs & new challenges in 2021, like new variants of #COVID19. At present, we are working closely with scientists to better understand any & all changes to the virus & how these changes affect its ability to spread, or any potential impact on available tools."

The mutant coronavirus strain is believed to be 70 percent more infectious.

It was reportedly first reported from the UK.