The number of coronavirus cases worldwide has topped 20 million, as the spread of the deadly disease continues to accelerate across the globe.

It took six months for the tally to hit 10 million, but just 43 days for it to double to 20 million.

The pandemic is spreading the fastest in Latin America, which accounts for about 28 per cent of all Covid-19 cases and more than 30 per cent of all deaths.

New Zealand's world-beating run of being virus-free ended on its 102nd day yesterday, after a family of four new confirmed cases of unknown source was detected. The government promptly put its largest city of Auckland under lockdown.

It is not all bad news, though.

Singapore yesterday recorded its lowest daily tally since April, with 61 new cases. Two of those were community cases.

Hong Kong, which has been battling a virus resurgence, also reported a sharp drop from figures since the start of last month - an indication that its outbreak is coming under control.

In Russia, President Vladimir Putin announced that his country has become the first in the world to approve a vaccine offering "sustainable immunity" against Covid-19.

The World Health Organisation and the Russian health authorities are discussing the process for WHO pre-qualification for the vaccine.