The World Health Organization's (WHO's) European director Thursday called Britain's approval of the Pfizer-BioNTech coronavirus vaccine "phenomenal" but urged Europeans to remain vigilant.

Speaking at his headquarters in Copenhagen, Dr. Hans Kluge said the Pfizer-BioNTech vaccine, the vaccines on the verge of approval elsewhere, along with 50 candidate vaccines currently in human trials, provide phenomenal promise. He said the vaccines, combined with other public health measures, can bring the end of an acute phase of the pandemic.

While the rest of Europe awaits the vaccine, Kluge called on nations to have plans in place and take immediate stock of their preparedness.

"This is a time for responsible leadership. To those countries seeing a decline in transmission: Use this time wisely," he said.

Considering the initial limited supply of vaccine that will be available, Kluge said WHO recommends health and social care workers, adults over 60 years of age and residents and staff of long-term care facilities should be prioritized.

He said nations should be scaling up public health infrastructure and preparing for the next surge. He warned that the virus still has the potential to do enormous damage "unless we do everything in our power to stop its spread."

Kluge said there have now been 19 million COVID-19 cases and over 427,000 deaths reported in the WHO European Region, with over 4 million more cases in November alone.

Last week, for the third consecutive week, the number of new cases declined, Kluge said, but Europe still accounts for 40% of new global cases and 50% of new global deaths.

He said the resurgence appears to be moving eastward, with the hardest hit countries now in central and southern Europe.