Infection numbers fall in China but coronavirus experts remain cautious

China’s Hubei province has reported its lowest number of new coronavirus cases since January, giving officials hope that the outbreak may be approaching its peak even as experts remained wary about its spread outside of China.

Health authorities in Hubei, the province at the centre of the outbreak, reported 1,638 new coronavirus cases on Tuesday, down from a peak of more than 3,000 new cases on 4 February and the lowest daily number of new infections since 31 January. National infection rates were also down.

Zhong Nanshan, an epidemiologist who is leading a government-appointed group working to control the outbreak, said on Tuesday that the numbers of new cases were falling in some provinces. He forecast that the epidemic could peak this month.

“I hope this outbreak or this event may be over in something like April,” he told Reuters. Zhong previously forecast an earlier peak that turned out to be incorrect.

As of midnight on Tuesday, China’s health commission said there were 2,015 new cases across the country, compared with 2,478 on Monday – a fall of 18.6%. The number of cases in China is now 44,653.

The death rate also fell across the country for the second time since the outbreak began. The number of new deaths reported as of midnight on Tuesday in China was 97. That compares with 108 reported for Monday – a fall of 10.2%. Of the new deaths, 94 were in Hubei province.

Experts remain alarmed by the spread of the virus, which has now killed more than 1,100 people, all but two in mainland China.

Asked about Zhong’s prediction, Australia’s chief medical officer, Brendan Murphy, said: “I think it’s far too premature to say that. I think we’ve just got to watch the data very closely over the coming weeks before we make any predictions.”

The World Health Organization has described the virus as a global threat potentially worse than terrorism. The world must “wake up and consider this enemy virus as public enemy number one,” the WHO chief, Tedros Adhanom Ghebreyesus, said on Tuesday, adding that the first vaccine was 18 months away.

Authorities have named the pathogen Covid-19 – CO for corona, VI for virus, D for disease and 19 for the year it emerged. Ghebreyesus said the goal of the name was to avoid stigma. For weeks some have called the outbreak the “China virus” or “Wu flu”, for Wuhan where the virus was first detected.

Public health experts caution that there are still many unknowns, including its lethality, mode of transmission, what groups are most vulnerable to the virus and the success of prevention and quarantine measures so far.

“Have these massive public health interventions, social distancing and mobility restrictions worked in China?” asked Gabriel Leung, chair of public health medicine at Hong Kong University and a leading coronavirus expert. “If so, how can we roll them out, or is it not possible?” He added: “We don’t know why it’s so contagious, so that’s a big problem.”

The incubation period, estimated to be between five and six days or up to 14 days, still requires more research. According to findings published on Sunday by Zhong and his team, the median incubation period is three days. One patient reported a 24-day incubation period.

Public health officials say it is still too early to predict when or if the outbreak will reach its peak in China. Next week, when more than 100 million citizens travel to return to work after the lunar new year holiday, will be critical for assessing whether the worst of the outbreak is over.

Experts fear the virus will continue to spread outside of China. Hundreds of cases have been reported around the world, including one fatality in Hong Kong and another one in the Philippines.

The biggest cluster of cases outside of China is onboard the Diamond Princess cruise ship quarantined off the Japanese port of Yokohama. Japanese officials on Wednesday said another 39 people had tested positive for the coronavirus, bringing the total to 174. A quarantine officer who boarded the ship to collect forms also tested positive.

Non-essential staff of the US consulate in Hong Kong have been authorised to leave the city on a voluntary basis, according to the US state department, which has announced similar measures for staff in mainland Chinese cities.

In Singapore, where 47 people tested positive to the virus, the bank DBS cleared a downtown office after one of its staff was confirmed to have contracted the virus. The bank said it had asked about 300 employees to work from home and it was trying to trace all possible contacts the infected employee may have had.

“It has spread to other places where it’s the beginning of the outbreak,”said Dale Fisher, head of the Global Outbreak Alert and Response Network coordinated by the WHO. “In Singapore we are at the beginning of the outbreak.”

Chinese authorities, nervous about the outbreak’s impact on the economy, have been pushing businesses and factories to reopen. The country’s education ministry cautioned university students graduating this year to be prepared for a “more complex and grim employment situation”.

People in Hubei province are meant to return to work on 14 February as the extended lunar new year holiday comes to an end.

“Wuhan has just passed the first 14 days [of quarantine]. Restarting work now would be the equivalent of repeating earlier disastrous mistakes. From the perspective of preventing and controlling the epidemic, this is not possible,” said Wang, 26, a teacher in the city.

Tuan Tuan, 31, who works in a bank in Wuhan, said: “We are all waiting to see if they extend the date. Nobody wants to [go back to work]. If we don’t hear in these two days of a postponement then we all have to go back.”

By mid-January at least 500 medical workers in Wuhan had contracted the virus, according to the South China Morning Post, citing medical sources.

China’s state news agency Xinhua said in an article on Tuesday that the epidemic was a “battle that has no gunpowder smoke but must be won”. It said the epidemic was a “big test of China’s governance system and capabilities” and some officials were still “dropping the ball” in places where it was most severe. “This is a wake-up call for us,” it said.

Meanwhile a Japanese official who visited the cruise ship held in quarantine off Yokohama, Japan, has tested positive for the virus, according to the New York Times.