620,000 told to self-isolate by virus app

“Without Chinese cooperation, WHO'S hands are tied, international hands are tied, and our ability to identify the origins of the virus will be much reduced.”

WHO Director General Tedros Adhanom Ghebreyesus last week announced a five-part plan for followup research on the origins of the coronavirus. It called for deeper study in geographical areas with early outbreaks, more research of animal markets in Wuhan, and audits of research labs near where the first cases emerged.

He also held a news conference in which he criticized China's cooperation, saying the country's government did not share “raw data” with the WHO team that visited Wuhan earlier this year to investigate the source of the initial outbreak.

The origin of the virus remains contested among experts.

The first known cases emerged in the central Chinese city of Wuhan in December 2019. The virus was believed to have jumped to humans from animals being sold for food at a city market.

In May, U.S. President Joe Biden ordered aides to find answers to questions over the origin, saying that U.S. intelligence agencies were pursuing rival theories potentially including the possibility of a laboratory accident in China.

White House press secretary Jen Psaki said on Thursday that the Biden administration is “deeply disappointed” in China's decision and told reporters that “their position is irresponsible and, frankly, dangerous.”

Zeng, along with other officials and Chinese experts at the news conference, urged the WHO to expand origin-tracing efforts beyond China to other countries.

“We believe a lab leak is extremely unlikely and it is not necessary to invest more energy and efforts in this regard,” said Liang Wannian, the Chinese team leader on the WHO joint expert team. More animal studies should be conducted, in particular in countries with bat populations, he said.

However, Liang said the lab leak hypothesis could not be entirely discounted but suggested that if evidence warranted, other countries could look into the possibility it leaked from their labs.

One key part of the lab leak theory has centred on the Wuhan Institute of Virology's decision to take offline its gene sequence and sample databases in 2019.

When asked about this decision, Yuan Zhiming, professor at WIV and the director of its National Biosafety Laboratory, told reporters that at present the databases were only shared internally due to cyber attack concerns.