'There is light at the end of the tunnel': WHO

Ghebreyesus appealed for $4 billion to buy COVID-19 vaccines for distribution in lower and middle-income countries through the COVAX vaccine facility.

"This is the challenge we must rise to in the New Year," Tedros said in a video message issued a day before the first anniversary of China reporting the first cases of pneumonia of unknown origin to the U.N. health agency.

He also urged countries to combat conspiracy theories and attacks on science, saying "The choice is easy," and the world can "walk the last miles of this crisis together, helping each other along the way, from sharing vaccines fairly, to offering accurate advice, compassion and care" to all who need them.

The COVAX alliance, which aims to secure fair access to COVID-19 vaccines for poor countries, said on Dec. 18 it had agreements in place for nearly 2 billion doses, roughly doubling its supply, with the first deliveries due in early 2021.