ATLANTA (AP) — As nations grapple with new outbreaks and spiking death tolls from the coronavirus, a commonly available drug appeared Tuesday to offer hope that the most seriously ill could have a better chance of survival.

The pandemic has forced countries to impose lockdowns and tough restrictions on daily life and travel, but infections have surged as they eased these rules and reopened their economies. With no vaccine available and much still unknown about the virus, researchers in England announced the first drug shown to save lives.

The drug, called dexamethasone, reduced deaths by 35 per cent in patients who needed treatment with breathing machines and by 20 per cent in those only needing supplemental oxygen, researchers in England said. It did not appear to help less ill patients.

British Prime Minister Boris Johnson said the drug was the “biggest breakthrough yet” in treating the coronavirus, and top US infectious disease expert Dr Anthony Fauci called it “a significant improvement in the available therapeutic options that we have.”

Britain is making dexamethasone available to patients on the country’s National Health Service. The UK Department of Health said the drug had been approved to treat all hospitalized COVID-19 patients requiring oxygen, effective immediately. It said the UK had stockpiled enough to treat 200,000 patients.

“It’s on almost every pharmacy shelf in every hospital, it’s available throughout the world, and it’s very cheap,” said Peter Horby of Oxford University, one of the leaders of the trial that randomly assigned 2,104 patients to get the drug and compared them with 4,321 patients getting only usual care.

Since the virus first emerged in China late last year and spread around the globe, there have been more than 8 million confirmed cases and more than 435,000 deaths.

The US death toll has reached 116,526, according to Johns Hopkins University. That surpasses the number of Americans who died in World War I, when 116,516 were killed — although both death tolls are far from precise. The United States has more confirmed cases and deaths from COVID-19 than any country in the world.

For most people, the virus causes mild or moderate symptoms, such as fever and cough that clear up in two to three weeks. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia and death. The vast majority of people recover but the more difficult cases last for weeks and sometimes take a bad turn even after symptoms seem to ease.

Countries that appeared to have largely contained the virus are seeing new outbreaks.

In China, authorities on Tuesday locked down a third neighbourhood in Beijing to contain an outbreak that has infected more than 100 people. Most of the cases have been linked to the capital’s Xinfadi wholesale food market, and people lined up for massive testing of anyone who had visited it in the past two weeks or come in contact with them. About 9,000 workers at the market were tested already.

New Zealand, which hadn’t seen a new case in three weeks, was investigating a case in which two women who flew in from London to see a dying parent were allowed to leave quarantine and drive halfway across the country before they were tested and found to be positive.

The re-emergence of the virus in the country once praised for how it handled infections raised the specter that international air travel could trigger a fresh wave of contagion just as countries are reopening airports to stimulate tourism.