Millions of people faced new coronavirus restrictions on Wednesday as infections surge, but in one sign of hope, an American firm said it would soon start final-stage human trials for a possible vaccine.

Countries around the world re-imposed lockdowns and curbs to contain new outbreaks, as global cases surged past 13.2 million with more than 576,000 deaths.

Hong Kong has made face masks compulsory on public transport as it battles a fresh coronavirus outbreak
Hong Kong has made face masks compulsory on public transport as it battles a fresh coronavirus outbreak AFP / Anthony WALLACE

Parts of the Asia-Pacific region, which had been somewhat successful in fighting the pandemic, provided fresh evidence of the deadly threat still posed by the virus.

Hong Kong's bars, gyms, and beauty salons closed again on Wednesday and a ban on gatherings with more than four people came into force as the city battled a fresh outbreak after months of impressive success against the virus.

Most of the city's residents voluntarily adopted facemasks as a barrier against the virus when it was first detected in mainland China late last year, but the Hong Kong government now requires passengers on public transport to wear them or risk a US$650 fine.

Graphic looking at countries with the highest coronavirus death tolls, and their respective death rates.
Graphic looking at countries with the highest coronavirus death tolls, and their respective death rates. AFP / John SAEKI

There was alarm in Japan too, where Tokyo's governor warned that the capital was on its highest coronavirus alert level after a spike in infections.

That came after the Indian state of Bihar, with a population of around 125 million, announced a 15-day virus lockdown starting Thursday. India's IT hub Bangalore has already started a week-long lockdown.

Members of the Chilean Police Canine Training team walk two golden retrievers before the beginning of their training session aimed at teaching the dogs to detect people infected with coronavirus
Members of the Chilean Police Canine Training team walk two golden retrievers before the beginning of their training session aimed at teaching the dogs to detect people infected with coronavirus AFP / MARTIN BERNETTI

Authorities in Australia, meanwhile, pleaded Wednesday with the public to heed social distancing guidelines, with roughly five million people in Melbourne in lockdown since last week in a bid to contain a new outbreak.

That request came just days after a group was fined Aus$26,000 (US$18,200) when their house party was exposed by an unusually large order of KFC.

"A particular concern for us is the ongoing parties and gatherings -- people playing poker, people holding parties," said Rick Nugent, acting assistant commissioner of Victoria state.

Brazilian President Jair Bolsonaro stands outside the Alvorada Palace in Brasilia. Bolsonaro tested positive for  coronavirus last week after months minimizing the dangers of the disease
Brazilian President Jair Bolsonaro stands outside the Alvorada Palace in Brasilia. Bolsonaro tested positive for coronavirus last week after months minimizing the dangers of the disease AFP / Sergio LIMA

"Please stop."

Londoners react after the British government's announcement that facemasks would be compulsory in shops and supermarkets in England from next week, in a U-turn on previous policy.
Londoners react after the British government's announcement that facemasks would be compulsory in shops and supermarkets in England from next week, in a U-turn on previous policy. AFPTV / Linda ABI ASSI

Such pleas from experts and authorities have been ignored and even mocked in many of the world's most populous parts, including the United States -- the worst-hit nation in the world.

Tens of thousands of cases are now being reported every day in the US as authorities scramble to roll back reopenings. The national 24-hour infection count was more than 63,000 on Tuesday, according to a Johns Hopkins University tracker.

Anthony Fauci, the top US infectious disease expert, again warned Americans against carelessness -- especially young people who may feel they are not vulnerable and would rather be "sipping my margarita at a bar in a crowd".

Given asymptomatic transmission, such young people "need to understand that given the nature of this outbreak... You are inadvertently propagating the pandemic, you are part of the problem and not the solution", Fauci said at an online Georgetown University event on Tuesday.

Hopes rose, however, when American biotech firm Moderna said it would start the final stage of human trials for its vaccine candidate on July 27, after promising results from earlier testing.

Moderna is considered to be in a leading position in the global race to find a vaccine, and while its study should run until October 2022, preliminary results should be available long before then.

With no vaccine or effective treatment widely available, experts have advised lockdowns and social distancing measures in some form to prevent the deadly pandemic from gaining even more momentum.

Face masks will become compulsory in England's shops and supermarkets from next week, while South Africa reimposed a nationwide curfew to prevent a "coronavirus storm".

In Cairo, Zeinab, a young mother, was struggling to survive by selling tissues when the coronavirus hit -- leaving her and thousands of other homeless people and street children even more vulnerable.

With fewer people in the streets, she said, "we have less work and less money".