BANGKOK (AP) — Japan could see some 850,000 people seriously sickened by the coronavirus and almost half of them dying if no social distancing or other measures are followed, according to an expert estimate released Wednesday.

Japan has the world’s oldest population, which is a particular concern since COVID-19 can be especially serious and fatal in the elderly. And there are concerns that Japan’s government has done too little and acted too late to stave off high numbers of seriously ill patients.

The current state of emergency is voluntary and doesn’t compensate workers who’ve lost earnings. Japanese companies also have been slow to adapt to remote work, meaning people still have continued to use public transit to commute to large offices in the densely populated capital region.

Already, patients are being moved to more hospitals and even hotels in Tokyo as infections surge in the capital, where medical experts warn the health care system is on the brink of collapse.

The projection by the government-commissioned team is a worst-case scenario, said Hokkaido University professor Hiroshi Nishiura, an expert on cluster analysis. He urged people to cooperate in the social distancing effort. “We can stop the transmission if all of us change our activity and significantly reduce interactions.”

The report projected 420,000 potential deaths because the seriously ill would require respiratory care or treatment in intensive care units and ventilators would run out if no preventive measures were taken, according to the report provided by the health ministry.

“If we are unprepared and hit by the pandemic, we will run out of respirators,” Nishitani told reporters.

Prime Minister Shinzo Abe had declared a state of emergency in Tokyo and six other prefectures on April 7 and asked people to curb their public activities. It was expanded nationwide Saturday. Nishiura expressed concerns that slowing infections would take longer if social distancing was limited.

An estimated 652,000 people 65 or older will become seriously ill under a hypothesis of one patient infecting 2.5 others, Nishiura said. An estimated 201,000 people from ages 15 to 64 would become seriously ill without social distancing and other preventive measures.

Japan currently has more than 8,800 cases of infection and 231 deaths, including about 700 positive cases from a cruise ship that was quarantined at a port near Tokyo earlier this year.

The health ministry reported 457 new cases on Wednesday. Tokyo has about a quarter of Japan's total cases and many of the sick patients are hospitalized. Officials are under pressure to expand space for more patients, while transferring those with no or slight symptoms to hotels to make room for others in serious condition.

So far, 105 patients who are slightly ill have been moved into a hotel, and Tokyo plans to secure up to 3,500 single rooms by June.

Hospitals that normally are not equipped to treat infectious diseases are being asked to take in patients. Medical experts have warned that Tokyo’s health care system is on the brink of collapse.

In other developments in the Asia-Pacific region:

— VACCINE STUDY ADVANCES: Chinese scientists have started the second phase of a clinical trial of a COVID-19 vaccine in the hardest-hit city of Wuhan in central China’s Hubei Province. China’s Central Television reported 273 out of 500 volunteers have been injected with the vaccine candidate. The first phase of the vaccine clinical trial focused on its safety, while the second phase studies its efficacy. China reported 46 new virus cases on Wednesday, 36 of them from overseas. Eight of the domestic cases were in Heilongjiang province bordering Russia, where authorities have been rushing to stem a new outbreak among those traveling back to China.

— NEW ZEALAND PAY CUTS: New Zealand's top officials are taking a 20% pay cut for six months in acknowledgment of the community’s sacrifices in dealing with the coronavirus. Prime Minister Jacinda Ardern says it applies to government ministers, chief executives of government organizations, and also that opposition leader Simon Bridges had volunteered to join them. She said it wouldn’t apply to any front-line staff like doctors or nurses. Ardern’s salary of $286,000 is a comparatively high amount for a country with only 5 million people.

— SOUTH KOREA VOTES: Voters wore masks and moved slowly between lines of tape at polling stations after the government resisted calls to postpone South Korea's parliamentary elections, seen as a midterm referendum on President Moon Jae-in. Long lines and record-high participation in early voting seemed to defy expectations of low voter turnout in the middle of a social-distancing campaign to slow infections.

— US CUTS WHO FUNDS: President Donald Trump has directed a halt to U.S. payments to the World Health Organization pending a review of its warnings about the coronavirus and China. He said the world depends on WHO to make sure accurate information about health threats are shared in a timely manner. Trump claims the organization failed to carry out its “basic duty” and must be held accountable.

— MANDATORY MASKS: Singapore has made masks mandatory following a sharp spike in new cases. Most people not wearing masks could be fined $212, while repeated offenders could face stiffer penalties. Infections in the tiny city-state have surged beyond 3,200 after two straight days of sharp increases. Many were among foreign workers living in crowded dormitories, and authorities are trying to test the workers more and reduce crowding.

— OPEN SCHOOLS MESSAGE: Australia’s prime minister is urging teachers to keep schools open for the sake of children’s education and the economy. Prime Minister Scott Morrison’s social media message comes as Victoria state schools resumed Wednesday after a term break and other states are considering their response. Morrison says that learning at home is not an option for some children, and that parents should not have to choose between holding down a job or caring for their families.

— SNEAKING OUT OF QUARANTINE: A man who repeatedly sneaked out of a hotel to visit his girlfriend has become the first person in Australia to be jailed for breaching a coronavirus quarantine order. Jonathan David, 35, was sentenced to six months and two weeks in prison but will likely only spend one month behind bars. He was also fined $1,280. David returned home to Perth from the Australian east coast on March 28 and was directed to spend the next two weeks in quarantine in a hotel, a standard requirement for interstate travelers. But he continually sneaked out and used public transport to visit his girlfriend.