The Delta variant is becoming the most dominant global strain as infections surge again in vaccinated countries like the UK and threaten unvaccinated regions like Africa, the WHO has warned.

The mutation, first identified in India, is taking over the world because of its extreme ability to spread with seemingly the most fleeting exposure.

“The Delta variant is well on its way to becoming the dominant variant globally because of its increased transmissibility,” said WHO’s chief scientist Soumya Swaminathan.

WHO’s warning comes as a NSW man contracted the virus just by going to the same shop as an infected limo driver who is at the centre of Sydney’s latest cluster.

The 50-year-old man appears to have picked up the virus at Myer Bondi Junction on Saturday where he had been on the same floor in the same section as the limo driver which health authorities described as “fleeting exposure”.

The rise of mutated coronavirus strains like Delta is also being blamed for the low success rate of another new vaccine in development which has failed to pass the WHO’s standards for approval.

• Related story: What it means as Australia runs short of Pfizer

CureVac’s jab was only 47 per cent effective in trials. Photo: Getty

German company CureVac cited the rise in variants when it this week reported its new jab proved only 47 per cent effective at preventing disease, shy of the WHO’s 50 per cent benchmark.

The company said it documented at least 13 variants circulating within its study population.

Dr Swaminathan voiced disappointment in the failure of CureVac’s vaccine candidate to meet the WHO’s efficacy standard, in particular as highly transmissible variants boost the need for new, effective shots.

The United Kingdom has reported a steep rise in Delta infections while Germany’s top public health official predicted it would rapidly become the dominant variant there despite rising vaccination rates.

The Kremlin blamed a surge in COVID-19 cases on reluctance to have vaccinations and “nihilism” after record new infections in Moscow, mostly with the new Delta variant, fanned fears of a third wave.

WHO officials said Africa remains an area of concern, even though the continent accounts for only about 5 per cent of new global infections and 2 per cent of deaths.

New cases in Namibia, Sierra Leone, Liberia and Rwanda have doubled in the last week, WHO emergencies program head Mike Ryan said while vaccine access remains minuscule.

“It’s a trajectory that is very, very concerning,” Mr Ryan said.

“The brutal reality is that in an era of multiple variants, with increased transmissibility, we have left vast swathes of the population, the vulnerable population of Africa, unprotected by vaccines.”

NSW enforces mask rules

Mask use is again compulsory on Sydney’s public transport after the 50-year-old man picked up COVID-19 from “fleeting exposure” at the Bondi Myer on Saturday.

A number of new exposure sites have also been announced across Bondi Junction, as well as Macquarie Park and at Sydney’s international airport.

The man’s symptoms began on Tuesday and he visited venues in Redfern, Newtown, Bondi Junction and Campbelltown while infectious.

• Exposure sites: See the list of NSW venues

The latest Sydney infection had only fleeting exposure at Myer in Bondi Junction. Photo: AAP

Queensland and Tasmania on Friday responded to the development by tightening border restrictions, with Queensland declaring a virus hotspot from 1am on Saturday in Sydney’s Waverley council area.

Tasmania will block entry for those who attended any NSW exposure site.

“This indicates that the initial case was highly infectious as transmission must have occurred through fleeting exposure,” Dr Chant told reporters.

“(This is) noting that the person who caught the infection at the cafe was seated outside and there was no known (contact) with the initial case.”

As a result, mask usage is again compulsory on Sydney public transport for at least the next five days, Premier Gladys Berejiklian announced.

The new case comes after an unvaccinated limousine driver from Sydney’s east and his wife were diagnosed with the coronavirus and subsequently infected a woman in her 70s at a Vaucluse cafe.

The limo driver, aged in his 60s, transported international air crews.
Another case – a man in his 40s from Sydney’s northwest – also tested positive for COVID-19, but NSW Health has not yet concluded if the case is genuine.

The woman in her 70s and the man in his 40s are included as new cases in the numbers for the 24 hours until 8pm on Thursday.

The man in his 50s will be included in numbers released on Saturday.

Meanwhile, Yates Avenue Public School in northwest Sydney was closed on Friday after a number of its staff attended a COVID-19 exposure site.

NSW Health on Friday evening listed a number of new COVID-19 exposure sites including the level five food court at Westfield Bondi Junction, as well as level four and the bus interchange near the centre.

It also listed Eden Gardens at Macquarie Park and the limousine car park at Sydney International Airport as new COVID-19 exposure sites.

The northwest Sydney man travelled to Canberra on Monday and the National Gallery of Australia and a cafe have also been deemed exposure sites.

The outbreak could mean NSW reintroduces some restrictions ahead of the school holiday period, which begins on June 26.

New Zealand Prime Minister Jacinda Ardern confirmed on Friday that quarantine-free travel will continue with NSW for the time being.

Western Australia and South Australia previously shut the border for those who attended the NSW virus exposure sites, while Victoria has tightened restrictions for residents of the City of Sydney, Waverley and Woollahra council areas.

-with AAP