The World Health Organization, or the WHO, on Monday urged people to exercise caution in the coming holiday season and pleaded governments for funding support to its vaccine facility.

WHO Director-General Tedros Adhanom Ghebreyesus said that the festival season is a time to relax and celebrate.

"But we must not relax our guard," he told a virtual press conference from Geneva.

The WHO has reported more than 66 million cases of COVID-19 worldwide and 1.5 million deaths. And the number of weekly deaths in the past six weeks has increased by about 60 percent. Most new cases and deaths are in Europe and the Americas.

"Celebration can very quickly turn to mourning if we fail to take the right precautions," Tedros warned.

He asked people to consider their plans carefully if they prepare to celebrate over the coming weeks, and they should take every precaution to keep themselves and others safe if they live in an area with high transmission.

"That could be the best gift you could give -- the gift of health, life, love, joy and hope," he said.

Maria Van Kerkhove, WHO's technical lead on COVID-19, echoed the views, saying people need to follow through all the precaution measures.

She warned that it's easy for the number of cases to go up but it takes a while for the number to go down.

Van Kerkhove, a US epidemiologist, said that she is going to celebrate this year's holiday via zoom.

On Monday, Tedros applauded the vaccine rollout in the United Kingdom and said he expects more countries to follow.

He said that the greater achievement would be to ensure all countries enjoy the benefits of science equitably, but WHO faces an immediate funding gap of $4.3 billion to procure vaccines for the most needy countries.

"I urge donors to fill this gap quickly so that vaccines can be secured, lives can be saved and a truly global economic recovery is accelerated," he said.

He said world leaders have made commitment for equitable access to vaccines, and he hopes to see that commitment being translated into action.

Already, WHO-led COVAXL vaccine facility, which is participated by 189 countries and economies but not the United States, has secured almost 1 billion doses of three vaccine candidates.

New York Times reported that the US Food and Drug Administration is accelerating timeline for issuing an emergency authorization for Pfizer's COVID-19 vaccine, likely on Friday evening local time. The US has the highest number of COVID-19 cases and deaths in the world.

However, not all vaccines being developed in the world have a smooth sail.

On Friday, GlaxoSmithKline and Sanofi announced that the roll-out of their jointly-developed coronavirus vaccine will be pushed back after it failed to show a sufficient efficacy in older patients.

The plan is to delay the vaccine until the fourth quarter of 2021 instead of the previous plan of rolling it out in the first half.

Bruce Aylward, senior advisor to Tedros, said that COVID-19 vaccines have offered hope and let people see the light at the end of the tunnel.

"It's a long tunnel," said the Canadian physician-epidemiologist, referring to the challenges of rolling out the vaccines to the wider population in the world and the still unsettled epidemiological situation of the novel coronavirus.