Australia's third-largest city of Brisbane was in its first day of a snap lockdown today, with officials elsewhere on "high alert" over the emergence of more contagious strains of Covid-19.

The usually bustling shopping strip in the city centre was eerily quiet Saturday, with only a small number of masked locals venturing out for essential reasons after officials announced a three-day lockdown from yesterday evening.

"Quite surreal, like something from a movie set," local man Scott told AFP, in an empty city street.

"It's necessary - hopefully we will get through the next few days without any cases, that will allow us just to start to get back to normal."

Highways into the city - which is usually a popular destination for Australian holidaymakers - were deserted as tourists were told to stay away until the lockdown ends.

The stay-at-home order for Brisbane's more than two million residents was triggered after the strain of the virus, first identified in southeast England, spread from a returned traveller to a cleaner at a quarantine hotel.

It was Australia's first recorded local case of the variant.

The strain is among several emerging variants around the world believed to be more infectious than those that have spread previously.

Authorities also issued a warning for passengers of a flight that arrived in Brisbane from Melbourne earlier this month, after a woman tested positive for the new strain despite already undergoing a period of isolation.

"The risk is extremely low - very, very, very low - because she (the traveller) is right at the end of her potential infectious period," Queensland's Chief Health Officer Jeannette Young told media.

"But because of this new variant, we're just being ultra-cautious."

The news comes as parts of Sydney prepared to end a weeks-long lockdown at midnight, following an outbreak which emerged last month.

New South Wales Health Minister Brad Hazzard said the state remained on "high alert" due to an increasing number of quarantined travellers testing positive for new variants of Covid-19.

"Obviously, there was a hope we might have entered 2021 with no Covid, but it's here to stay," he added.

Fears of a more infectious strain spreading through the community prompted Australia to announce a temporary cut to international arrivals and tighten quarantine arrangements.

Until the lockdown, Brisbane had been among several Australian cities enjoying a return to relative normality due to the country's success in suppressing the virus.

Australia has recorded more than 28,500 Covid-19 cases and 909 deaths linked to the virus, in a population of about 25 million.

Latest coronavirus cases

US coronavirus cases passes 21.82 million

The total number of Covid-19 cases in the United States had surpassed 21.82 million as of yesterday evening, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University.

The national case count had risen to 21,827,402, with 368,367 relevant deaths, as of 7.22pm Eastern Standard Time (EST) yesterday, according to the CSSE tally. 

Los Angeles County, the most populous county in the United States, reported yesterday 318 coronavirus-related deaths in the past 24 hours, the first time that more than 300 daily new deaths were counted. 

The 318 new deaths pushed the countywide coronavirus death toll to 11,863. By comparison, an average of 170 people die of all other causes in the county every day and the number is higher than any other single yearly premature deaths, including heart disease.

The county reported another 18,313 coronavirus cases yesterday, one of the highest number of daily new cases, bringing the overall tally since the start of the pandemic to 889,405.

The Covid-19 outbreak continued to worsen across California, with nearly 2.6 million confirmed cases and 28,634 deaths as of 4.22pm Eastern Standard Time (EST) yesterday.

It is reported that California's emergency services sent 88 refrigerated trailers to the worst-hit counties and cities across the state to temporarily store bodies.

China sets up 25,392 inoculation sites

China has set up a total of 25,392 inoculation sites nationwide for vaccinating priority groups prone to COVID-19 infection, an official of the National Health Commission (NHC) has said. 

Cui Gang, director of the Epidemic Prevention Bureau of the NHC, said that the commission has organised experienced experts to make eight technical plans for vaccination, including preparations, reasonable site setup, on-site organisation and implementation, distribution and transport of vaccines as well as monitoring to prevent abnormal physical reactions, to provide detailed technical preparations for local vaccinations. 

Zeng Yixin, deputy director of the NHC, said that "we formally launched the vaccinations for priority groups in our country on December 15.

WHO calls for equitable distribution of vaccines

All countries around the world should commit to equitable distribution of Covid-19 vaccines and achieve accessibility, affordability of the vaccines regardless of poor or rich states, said the World Health Organization (WHO) director-general Tedros Adhanom Ghebreyesus recently. 

According to Mr Tedros, 42 countries have implemented safe and effective vaccination, of which 36 are high-income countries and six are middle-income countries. 

However, most of the low-income and most middle-income countries have not yet received the vaccines, with majority of the available vaccines having been purchased by the rich countries. 

Mr Tedros cautioned that this may potentially markup the price of vaccines, making high-risk groups in the poorest and most marginalized countries have no access to vaccination.

Therefore, people in all countries should be vaccinated fairly, Mr Tedros noted. Equitable vaccine distribution can not only save lives, but also stabilize the health system, to promote global economic recovery.