The World Health Organization Director-General Tedros Adhanom has hailed as "incredible" the development of a COVID-19 vaccine less than 12 months since the deadly virus was reported.

"It is incredible to think that less than a year ago, we had not even heard of this virus, and now we have an approved vaccine against it," he said on Thursday.

Tedros' remarks came a day after the U.K. became the first country to approve a COVID-19 vaccine as the world continues its fight against the virus.

The 55-year-old acknowledged that not all countries will be able to receive vaccine doses at the same time, but issues an assurance that countries will receive the vaccines as supplies increase.

"WHO has an unwavering commitment to equitable, timely and fair access to all the tools that can serve to mitigate and end this pandemic, including vaccines," he said.

By Thursday, the number of confirmed COVID-19 infections globally had surpassed the 64.72 million mark with a death toll exceeding 1.49 million.