The WHO warned that rich countries cannot use boosters to escape the coronavirus, as nations scrambled to contain Omicron surges.

"No country can boost its way out of the pandemic," said the World Health Organization's Secretary General Tedros Adhanom Ghebreyesus on Wednesday evening.

"Blanket booster programmes are likely to prolong the Covid-19 pandemic, rather than ending it, by diverting supply to countries that already have high levels of vaccination coverage, giving the virus more opportunity to spread and mutate."

Nor should a third dose of vaccine be seen as carte blanche, he added. "Boosters cannot be seen as a ticket to go ahead with planned celebrations".

Unrestrained end-of-year celebrations could still prove to be major source of new infections, the WHO warned.

The threat of the highly mutated Omicron variant is looming large over the end-of-year holidays, pushing many governments to roll out new restrictions and urge citizens to get vaccinated.

The latest data suggest Omicron does not cause more severe illness than previous variants, including Delta, but as soaring infection numbers threaten to overwhelm health systems, scientists warn it could still cause more deaths.

Germany's Robert Koch Institute for infectious disease confirmed the country's first death due to the Omicron variant yesterday.

The person was between the age of 60 and 79, the institute said.

The states across India have begun clamping down fresh curbs on large gatherings in the run up to Christmas and New Year celebrations, reports our New Delhi correspondent.

The curbs reimposition came a day after the Indian Health Minister cautioned about faster spread of Omicron and noting its "initial signs of surge."

In UK, official estimates showed yesterday that around 1.2 million people were likely infected with Covid-19 last week, representing 1 in 45 of the population and a new pandemic record as the Omicron variant spreads rapidly.

London was worst hit with an estimated 1 in 30 people infected with the coronavirus last week, according to the figures from the Office for National Statistics, reports Reuters.

Scotland announced that it will close nightclubs from next week to fight the spread of Covid-19.

The National Health Institute in Italy said yesterday that the Omicron variant is spreading rapidly, releasing preliminary data of a flash-survey showing it accounted for 28% of cases on December 20. The previous survey showed Omicron at just 0.19% of cases on December 6.

The United States on Wednesday authorised Pfizer's anti-Covid pill for high-risk people aged 12 and up, as a surge of cases driven by the highly infectious Omicron variant threatened holiday plans and Americans struggled to find tests.

Paxlovid, which comprises two types of tablet, was granted an emergency use authorisation by the Food and Drug Administration (FDA) after a clinical trial showed it to reduce the risk of hospitalisations and deaths among at-risk people by 88 percent.

British pharmaceutical giant AstraZeneca said yesterday that a third, or "booster", dose of its Covid-19 vaccine Vaxzevria "significantly" lifted antibody levels against the Omicron strain in a laboratory study.

AstraZeneca also revealed in other findings that its preventative moniclonal antibody treatment, Evusheld, "retains neutralisation activity" against Omicron.