South Korea, once one of the hardest-hit countries in the coronavirus pandemic, reported no new cases on Thursday, boosting hopes of an eventual return to normality as US scientists hailed the results of a major drug trial.

A homeless man in Moscow gets a meal at s has a meal at the "Rescue Hangar" during the COVID-19 coronavirus lockdown
A homeless man in Moscow gets a meal at s has a meal at the "Rescue Hangar" during the COVID-19 coronavirus lockdown AFP / Dimitar DILKOFF

The good medical news caused equities to rally, despite mounting deaths worldwide and abysmal economic figures caused by the COVID-19 crisis.

Data showed the pandemic, which has killed more than 224,000 people, has plunged the United States into its worst economic slump in a decade, and has left Germany expecting its biggest recession since the aftermath of World War II.

A homeless man in Moscow gets a meal at s has a meal at the "Rescue Hangar" during the COVID-19 coronavirus lockdown
A homeless man in Moscow gets a meal at s has a meal at the "Rescue Hangar" during the COVID-19 coronavirus lockdown AFP / Dimitar DILKOFF

But for the first time since the new disease was detected there in mid-February, South Korea reported zero new infections.

A nurse awaits his next patient at a mobile COVID-19 testing station in a public school parking area in Compton, California
A nurse awaits his next patient at a mobile COVID-19 testing station in a public school parking area in Compton, California AFP / Robyn Beck

The East Asian nation had the world's second-largest coronavirus outbreak for a period after the virus emerged in China late last year.

But with an aggressive test-and-trace strategy and widespread social distancing, it has managed to bring the spread of the pathogen under control.

Lebanese demonstrators walk through the streets of the capital Beirut as anger over a spiralling economic crisis re-energised a months-old anti-government movement
Lebanese demonstrators walk through the streets of the capital Beirut as anger over a spiralling economic crisis re-energised a months-old anti-government movement AFP / ANWAR AMRO

"This is the strength of South Korea and its people," said President Moon Jae-in as he announced the milestone.

Health workers help a woman who tested positive for the novel coronavirus COVID-19,  at Bagcilar in Istanbul
Health workers help a woman who tested positive for the novel coronavirus COVID-19, at Bagcilar in Istanbul AFP / Bulent Kilic

Meanwhile in the first proof of successful treatment, a clinical trial of the drug remdesivir showed that patients recovered about 30 percent faster than those on a placebo.

"The data shows that remdesivir has a clear-cut, significant, positive effect in diminishing the time to recovery," said Anthony Fauci, the top US epidemiologist.

Inmates from Villa Devoto prison take part in a riot demanding measures to prevent the spread of the Covid-19 coronavirus, after a case was reported inside the detention center, in Buenos Aires
Inmates from Villa Devoto prison take part in a riot demanding measures to prevent the spread of the Covid-19 coronavirus, after a case was reported inside the detention center, in Buenos Aires AFP / JUAN MABROMATA
Workers build 700 graves at the Mezquitán Pantheon cemetery in preparation for possible victims of the novel COVID-19 coronavirus in Guadalajara, Mexico
Workers build 700 graves at the Mezquitán Pantheon cemetery in preparation for possible victims of the novel COVID-19 coronavirus in Guadalajara, Mexico AFP / ULISES RUIZ

South Korea's virus death toll is around 250 -- vastly lower than that of Italy, Britain, Spain and France, which have each recorded more than 24,000 fatalities, and the United States, topping the table with a third of global deaths.

A man dressed as 'Yamraj', the Hindu mythical angel of death, campaigns to raise awareness on the importance to stay home and maintain social distancing during an event organised by Delhi police
A man dressed as 'Yamraj', the Hindu mythical angel of death, campaigns to raise awareness on the importance to stay home and maintain social distancing during an event organised by Delhi police AFP / SAJJAD HUSSAIN

Other parts of the region have seen similar success in their fight against the virus.

Infections have dwindled in China after it imposed extremely strict lockdown measures on millions of people earlier this year. Its official toll is around 4,600, although doubt has been cast on the figures' accuracy.

A selection of over 125,000 birthday cards sent to Captain Tom Moore, for his 100th birthday on April 30th, displayed in the Great Hall of Bedford School, in Bedford, north of London
A selection of over 125,000 birthday cards sent to Captain Tom Moore, for his 100th birthday on April 30th, displayed in the Great Hall of Bedford School, in Bedford, north of London AFP / JUSTIN TALLIS

Hong Kong, a city of seven million where there have been just four virus deaths, reported no new cases for the fifth straight day on Thursday.

People wearing face masks visit a hair salon in Tokyo
People wearing face masks visit a hair salon in Tokyo AFP / CHARLY TRIBALLEAU

And New Zealand has declared the battle won against widespread, undetected community transmission.

However the economic costs are beginning to mount, raising fears of an era-defining global crash and increasing pressure worldwide to ease lockdowns despite fears of a second wave of contagion.

A man wearing a face mask and his child observe a California Sea Lion at Berlin's Zoo as it partially reopens for the public
A man wearing a face mask and his child observe a California Sea Lion at Berlin's Zoo as it partially reopens for the public AFP / Tobias SCHWARZ
Even during a strict lockdown, anti-poaching rangers in South Africa's Greater Kruger Park area continue on the front lines to guard one of the country’s most precious resources: its wildlife.
Even during a strict lockdown, anti-poaching rangers in South Africa's Greater Kruger Park area continue on the front lines to guard one of the country’s most precious resources: its wildlife. AFPTV / Antoine DEMAISON

The US announced that economic output collapsed 4.8 percent in the first quarter -- ending more than a decade of expansion.

On Thursday, France and Spain both said their economies had fared even worse, contracting 5.8 percent and 5.2 percent respectively, while the Eurozone economy as a whole also shrank.

Federal Reserve chairman Jerome Powell warned worse was to come, and economic activity will likely drop "at an unprecedented rate" in the second quarter.

Germany, Europe's largest economy, has succeeded in holding off the devastating death tolls seen elsewhere, but is still bracing for an overwhelming economic hit.

Germany "will experience the worst recession in the history of the federal republic" founded in 1949, Economy Minister Peter Altmaier warned, predicting that GDP would shrink by a record 6.3 percent.

The International Labour Organization said half the global workforce -- around 1.6 billion people -- are in "immediate danger of having their livelihoods destroyed".

One of the worst-hit sectors is the aviation industry, but an unprecedented drop in demand for fossil fuels means global energy emissions are expected to fall a record eight percent this year, the International Energy Agency said.

Experts have warned that only a vaccine will allow the full removal of restrictions that this year put half of humanity under some form of lockdown.

But there have been encouraging signs in the search for a treatment.

Fauci likened remdesivir to the first retrovirals that worked, albeit with modest success, against HIV in the 1980s.

The drug failed in trials against the Ebola virus, and a smaller study, released last week by the WHO, found limited effects among patients in the central Chinese city of Wuhan, the disease's original epicentre.

Senior WHO official Michael Ryan declined to weigh in on the latest findings, saying he had not reviewed the complete study.

"We are all hoping -- fervently hoping -- that one or more of the treatments currently under observation and under trial will result in altering clinical outcomes" and reducing deaths, he said.

While the world keeps looking for signs of progress against the pandemic, research is also revealing frightening new details about COVID-19.

Britain and France have both warned of a possible coronavirus-related syndrome emerging in children -- including abdominal pain and inflammation around the heart.

"I am taking this very seriously. We have absolutely no medical explanation at this stage," French Health Minister Olivier Veran said.

Experts have also warned of longer-term psychological tolls on both children and adults after weeks or even months in isolation.