The number of new infections in China's Hubei province, the epicenter of the outbreak, rose on Friday from a day earlier, Chinese health officials said, reversing two days of declines and showing the difficulty of predicting the epidemic's peak.
The death toll in mainland China jumped by 86 to 722, and is poised to pass the 774 deaths recorded globally during the 2002-2003 pandemic of Severe Acute Respiratory Syndrome (SARS), another coronavirus that jumped from animals to humans in China.
So far only two deaths have been reported outside mainland China - in Hong Kong and the Philippines - from about 332 cases in 27 countries and regions.
During the SARS outbreak between November 2002 and July 2003, 774 people died globally, while the number of reported cases was 8,098, suggesting a far lower transmission rate than the latest coronavirus, but a higher mortality rate.
After China recorded its first daily drop in the number of new infections on Thursday, the World Health Organization (WHO) said it was too early say whether the outbreak had peaked.
The first cases in December were traced to a seafood market in the Hubei capital of Wuhan, where wildlife was sold illegally.
"It is hard to say how lethal this novel coronavirus infection is - that is, what proportion of people with infection will eventually die of the infection," Professor Allen Cheng, an infectious diseases expert at Monash University in Melbourne, told Reuters.
"While the crude mortality appears to be around 2%, there are likely to be many people who have been infected that haven't been tested ... We probably won't know the true case fatality for some time yet."
Hubei officials on Saturday reported 81 new deaths, 67 of those in Wuhan, a city under virtual lockdown. Across mainland China, excluding the 2,050 people who had recovered and those who had died, the number of outstanding cases stood at 31,774.
Beijing's communist leadership has sealed off cities, canceled flights and closed factories to contain the epidemic, with ripple effects for global markets and businesses dependent on the world's second-biggest economy.
WHO experts say they have not seen the same rapid increase in cases in provinces outside Hubei, or in the Chinese territories of Hong Kong and Macau that were badly hit by SARS.
Speaking in Geneva, WHO chief Tedros Adhanom Ghebreyesus cautioned earlier that "the numbers could go up again."
FALSE NEGATIVES
Not all of the infected will test positive for the virus, warned Wang Chen, head of the Chinese Academy of Medical Sciences.
"For patients who are really infected with the new type of coronavirus, the positive rate for tests is 30% to 50%," Wang told state television in an interview that has gone viral on social media since its telecast on Wednesday.
"There are still many false negatives by collecting suspected cases of throat swabs. In other words, more than half of the people who are truly infected with the new coronavirus may be 'negative'."
Hubei has started to use computerized tomography (CT) scans for quicker and more accurate test results.
Memories of how China was slow to tell the world about the SARS outbreak were rekindled on Friday when a doctor who had tried to raise the alarm about the new coronavirus succumbed to the disease in a Wuhan hospital.
Ophthalmologist Li Wenliang, 34, was among eight people reprimanded by police in Wuhan for spreading "illegal and false" information after he shared details of the virus with colleagues.
Social media users called him a hero and shared a selfie of him lying on a hospital bed wearing an oxygen respirator and holding up his Chinese identification card. One image showed the message "farewell Li Wenliang" etched into snow on a riverbank.
There were signs that discussion of Li's death was being censored. After briefly trending on Weibo, the topics "the Wuhan government owes doctor Li Wenliang an apology" and "we want free speech" yielded no search results.
LACK OF MASKS, GOWNS
The WHO chief warned of worldwide shortages of gowns, masks and other protective equipment.
"When supplies are short and demand is high, then there could be bad practices like hoarding in order to sell them at higher prices, and that's why we ask for solidarity," Tedros told a Geneva briefing.
Another three people on a cruise liner off Japan tested positive for coronavirus, bringing the total number of confirmed cases from the ship to 64, Japan's health ministry said on Saturday.
Royal Caribbean Cruises Ltd on Friday banned "any guests holding a Chinese, Hong Kong or Macau passport, regardless of when they were there last" from boarding the company's ships.
WHO emergency expert Mike Ryan said reports of Asians being shunned in the West over a perceived connection to coronavirus was "utterly and completely unacceptable and it needs to stop."
Taiwan’s government said that starting from Monday it would suspend all direct passenger and freight shipping between the island and China. It had already decided to suspend most flights from Monday between Taiwan to China.
Hundreds of foreigners have been evacuated out of Wuhan over the past two weeks. A second evacuation plane to airlift Australians out of Wuhan was delayed after China did not give it clearance to land, Australian officials said on Saturday.
Global equity markets and government debt yields slumped on Friday, as growing concerns about the virus' impact on global growth overshadowed a strong U.S. jobs report.
Apple Inc, however, said it was working to reopen its China corporate offices and call centers next week, and was making preparations to reopen retail stores there.
U.S. Secretary of State Mike Pompeo on Friday said the United States was prepared to spend up to $100 million to assist China and support coronavirus efforts by the WHO.
The United States has sent nearly 17.8 tons of medical supplies to China, including masks, gowns and respirators, a State Department official said.
The WHO said out of $675 million it is seeking for its coronavirus response through April, it has received pledges of $110 million, $100 million of that from the Gates Foundation.