Several EU nations were set to begin vaccinating their most vulnerable groups Sunday as a new coronavirus variant spread internationally and the WHO warned the current pandemic will not be the last.
The first doses of the Pfizer-BioNTech jab arrived in hard-hit Italy, Spain and France on Saturday, ready for distribution to retirement homes and care staff.
The approval and roll-out of vaccines has boosted hopes that 2021 could bring a respite from the pandemic, which has killed more than 1.7 million people since emerging in China late last year.
However, in a video message ahead of the first International Day of Epidemic Preparedness, World Health Organization chief Tedros Adhanom Ghebreyesus said it was time to learn the lessons from the Covid-19 pandemic.
"History tells us that this will not be the last pandemic, and epidemics are a fact of life," said Tedros.
"Any efforts to improve human health are doomed unless they address the critical interface between humans and animals, and the existential threat of climate change that's making our Earth less habitable," he added.
A 101-year-old woman in a care home became the first person in Germany to be inoculated Saturday, in what the country's health minister called a "day of hope".
The first jabs were also handed out in Hungary and Slovakia.
The three countries joined China, Russia, Britain, Canada, the United States, Switzerland, Serbia, Singapore and Saudi Arabia, which have also begun their vaccination campaigns.
"We'll get our freedom back, we'll be able to embrace again," Italian Foreign Minister Luigi Di Maio said as he urged his compatriots to get the shot.
But polls show only 57 percent of Italians intend to get the jab, whereas scientists estimate herd immunity can only be reached if 75 to 80 percent have it.
Flare-ups of the virus continue to force tougher restrictions, with Israel going into a two-week general lockdown from Sunday and France's health minister saying his government would take similar steps in the event of a post-Christmas spike.
Jitters also remained over a new strain that has emerged in Britain and reached several other European countries and Japan.
Four cases were confirmed in Madrid on Saturday, though the patients were not seriously ill, according to health official Antonio Zapatero, who said "there is no need for alarm."
Canada reported Saturday that it had detected two variant cases in the province of Ontario in a couple who had not travelled recently nor had high risk contacts with other people.
The new strain, which experts fear is more contagious, prompted more than 50 countries to impose travel restrictions on the UK.
Ahead of a WHO probe into the disease's origins, China's communist leadership issued a statement hailing the "extremely extraordinary glory" of its handling of the virus, state media reported.
China has largely curbed the domestic spread of the virus, and was one of the only major economies to report growth this year. But it has been accused of covering up the initial outbreak, and so contributing to the virus' spread internationally.
Australian golf great Greg Norman became the latest well-known name to quarantine, saying on Saturday he was isolating at home after spending Christmas Day in the hospital with Covid-19 symptoms.
Across the world, people were still being urged to respect social distancing guidelines, even as millions celebrated Christmas.
Switzerland's health minister Alain Berset noted Saturday his country had put the emphasis on personal responsibility.
But he admitted that had not worked and that the government blundered in easing restrictions too far, resulting in some of Europe's fiercest infection rates during the pandemic's second wave.
In authoritarian post-Soviet Turkmenistan, where the government says no coronavirus cases have been detected, President Gurbanguly Berdymukhamedov claimed that licorice root could cure Covid-19.
"Licorice stops the coronavirus from developing," former dentist Berdymukhamedov said, without citing any scientific evidence.
Turkmenistan has "sufficient reserves" of licorice, he added, ordering the national academy of sciences to study the plant's supposed health effects.